One consequence of the addition of dashing is that dodging projectiles and slam attacks from Knight-type enemies became much easier. Normally when changing strafing directions in an FPS, your velocity is briefly reset and have to re-accelerate to top speed, leaving you briefly vulnerable to incoming shots while your velocity is still low, and in the case of avoiding Hell Knight leaps you are boned if you weren’t at max velocity when the Knight initiated the leap. But dashes can instantly accelerate you to top speed in any of the eight cardinal directions. To compensate,
the attack token system that governs how many enemies were allowed to attack at once seems to be much more lenient in Eternal compared to nuDoom. All fodder enemies always seem to be attacking you at once, and more of them use their charge attacks at once. Another new measure to balance out dashing is that more enemy types will fire projectiles in bursts, which can effectively box you in (at medium range). For example, if you strafe/dash right, there will be a stream of projectiles to your left, cutting you off from one direction and leaving you open to projectiles with leading, forcing you to either tank the damage or use your vertical mobility options to simply hop over the projectiles.
The rest of your Equipment has also been retooled: now the Frag Grenade is actually useful with its larger AoE and being able to consistently falter even heavier demons for an opening, and the new Ice Bomb acts as a get-out-of-jail-free card by letting you freeze a group of enemies, where damaging frozen enemies also drops extra health. It’s a lot more useful than nuDoom’s Equipment, whose effectiveness was marginal at best, or in the case of the Hologram you weren’t entirely sure whether it actually worked.
In nuDoom, you often forgot about your Equipment items because not only was their usefulness marginal, it also briefly made you unable to fire your gun. By posing the use of Equipment as an either/or choice, the most versatile option usually wins out (in this case just shooting enemies with your gun) because it minimizes the downtime of switching weapons/lowering your gun and being unable to attack. So with either/or choices, options with more (comparatively) marginal benefits and situational use draw the short straw.
What Eternal then did is mount the Equipment Launcher on your shoulder, allowing you to use Equipment
while firing your gun. Even if using the new Flame Belch/Frags/Ice Bomb isn’t worth it over just being able to shoot and switch weapons, it doesn’t matter because now you can do both at the same time with no additional cost (other than the mental effort of doing more things at once). The old binary system could have been justified by buffing Equipment to be a worthwhile trade-off over being briefly unable to use weapons, but downplaying the binary commitment allows less-versatile options to be more relevant,
and allows for larger combo potential.
In the frenzy of combat it’s easy to forget about your Equipment, as the rest of the combat in Eternal already takes up tons of concentration. But if you died and know that you forgot about the Flame Belch and Frags and Ice Bomb, then you know how to improve your chances of survival next time. And knowing what to improve on and how to improve on it is what motivates players to keep trying. Saying they’re just there to rotate through as soon as they come off cooldown is being reductive, considering there’s still opportunity costs attached to igniting or faltering more enemies at once with the Flame Belch/Frag respectively as opposed to using it on just one enemy.
But of the Ice Bomb I’m not a fan. It’s basically the Stun Bomb from 2016, only now it has a much longer cooldown so you can’t spam it as much. But the core problem remains: it simplifies interacting with tons of enemies. For example, it shuts down the Whiplash’ mobility, it lets you safely circle towards a Pinky’s back to finish it off, it lets you safely walk up and Blood Punch off a Cyber-Mancubus’ armor without having to deal with its close-range shockwave attack, it allows you to easily shoot Weak Points off enemies as they’re frozen in place, and it allows you to dump tons of damage into a Super-Heavy demon so you can kill them before they have the chance to even counter-attack. There is no skill involved in using it beyond aiming somewhere where you can freeze the most enemies, and in terms of resources it’s very forgiving because it works off its own cooldown that’s not shared with anything else. Especially once upgraded the Ice Bomb becomes even more powerful than it should. The combat is more interesting when the enemies get the opportunity to actually move around and be a threat, so if you want to keep things interesting for yourself you should ideally never use the Ice Bomb at all. As it is, the Ice Bomb is just a crutch for newer players, but the game never gives you a reason not to use the readily-available tool that simplifies combat.
On the other hand, the Frag Grenades are more reasonable because all they do is deal damage and briefly falter enemies instead of taking them out of the picture completely. There would be a more interesting trade-off to the Ice Bomb if it shared resources with something else, like the Frags. So you can either choose to spend two charges from a maximum of two for an Ice Bomb, or one charge for one Frag, of which you can quickly fire two. Defensive player would lose out on the Frags to use the Ice Bomb, whereas aggressive players would sooner rely on the versatility of two Frags than the Ice Bomb crutch. Alternatively, the Ice Bomb could keep its get-out-of-jail-free card role without being downright broken if damage dealt against frozen enemies was massively reduced and if it wasn’t possible to break the Weak Points of frozen enemies. That way the Ice Bomb can still save your hide in a tough position, but it won’t let you effortlessly dispatch enemies since you can’t damage them that much; at most it just delays them. It should be noted that frozen enemies already take less damage than normal, but a suit upgrade which just lets you do normal damage against them instead.
There’s also a more general topic I want to address here, which is Eternal’s usage of cooldowns. Cooldowns are a valid way of balancing the power of certain options, but they come with two caveats: they enable stalling, meaning newer players will opt to back away from the action until the cooldown is refilled, and they lower the skill ceiling because a higher-level player is inevitably restricted by the cooldown (unless there’s a way to reduce the cooldown through proactive play, as with the Equipment Fiend Rune in Eternal). Stalling is less of a problem in games with time limits or games that snowball you to death if you don’t play proactively, but it’s still possible to stall in Eternal what with all the movement options afforded to you. So I’ve already read several online complaints about people thinking it’s only possible to deal with Whiplashes/Cyber-Mancubi with an Ice Bomb, and having to stall before they can begin to deal with them. While the most obvious response might be to call these people scrubs and that they’re playing the game wrong, it’s still a failure on the game’s part to allow them to play the game that way and still win.
One approach that would be very much in line with the rest of the game is to have your Equipment only recharge by killing enemies (á la potions in Path of Exile). It would further discourage passive play in favor of going out there and killing shit, and it would reward better players by letting them use their Equipment more often the faster they kill. A hybrid solution could also be used where there’s still a cooldown, but it’s longer than a minute and only there to recharge your Equipment inbetween arenas, so the most reliable way of recharging it is still to kill shit.
Another thing hampering the Equipment system (and resource management) is the UI: Eternal tucks away all status indicators and ammo counters in the bottom right in the screen, which with the intensity of Eternal’s combat you’ll have almost no time to glance at, while it’s also too small to be picked up in your peripheral vision. Instead I found myself relying more on intuition on when my Equipment was ready and how much ammo I had, which tended to backfire time to time. Ideally, all UI indicators would be positioned around the crosshair, where you would actually be focusing your eyes during combat. With the increased focus on ammo management and weapon switching, knowing how much ammo you have for other weapons you plan switching to is important. Unfortunately Eternal only shows you the ammo for your current weapon, so I often found myself switching to another mainstay weapon, only to find out the hard way that it has no ammo. Some ammo count indicators for all your ammo types (as the original Doom did, or more usefully what Quake Live did by displaying them at the left/right side of the screen) would be useful here.
That said, the visual clarity of Eternal has been improved. nuDoom was dominated by the red, orange and black colors, which made it more difficult than necessary to tell apart enemies from the background at a glance. By contrast, the locales in Eternal are much more varied and colorful, making enemies to stand out more. Another underrated facet to knowing what enemies you’re dealing with is the enemy projectile colors/shapes. Even if you haven’t directly seen the enemy, you can tell by the projectiles that a particular enemy type is out and about. Yellow/green-ish means its a Gargoyle, a set of three rings means its a Carcass, a large horizontal wave means its a Dread Knight/Baron, blue/red-ish means its a Cacodemon, a Lost Soul means its a Pain Elemental, purple means its a Prowler, and so on. Regrettably the sound mix is still too muddled to be able to tell where the sounds the demons are making coming from. There are some exceptions this time around that are able to give you useful information based on their sound: the Whiplash makes a noticeable passive hissing sound when it’s nearby, and the Cyberdemon’s beam makes a very noticeable charging sound before it is about to fire. But these are still exceptions to the rule.
The Glory Kill mechanic has also seen some changes. Instead of dropping a useless +5HP, now Glory Kills will always drop at least +20HP, which is usually more worth it. But more importantly, Glory Kills have become a lot safer to do now with the introduction of dashing. You can immediately dash away from a bad position once the Glory Kill ends, especially with the upgrade that refreshes your dash charges on a Glory Kill. This makes Glory Kills a bit
too safe to perform, and further encourages players to spam it without considering whether they will get pummeled with a meaty once the invincibility ends (because they know they won’t); further bolstering the perception of Glory Kills as a braindead cosmetic finisher instead of a move with relevant risks and rewards. It’s still possible to have your dash bodyblocked by a demon, and Mancubi can consistently punish you for recovering from a Glory Kill in their shockwave range, but a good majority of the time you can just dash away from a Glory Kill while taking no or minimal damage. This holds doubly true when you have the Savagery (Faster Glory Kills) and Blood Fueled (get a speed boost after a Glory Kill) Runes equipped, whose speed boost is much more powerful in Eternal compared to nuDoom (for the record, I like that Blood Fueled lets you go even faster now and wouldn’t want to change it, but it does make Glory Kills less risky).
Glory Kills could be a proper trade-off if the AI actively tried to surround and bodyblock you, but esp. with Savagery the Glory Kills wouldn’t last long enough to give the AI time to do so. A more controversial approach would be to remove the invincibility entirely but make Glory Kills twice as fast to compensate; now that enemies can freely damage you, you have to actually decide whether the situation is safe enough or create a situation where you can Glory Kill without getting hit during by enemies. A hybrid solution is to keep the invincibility, except for the tail end of the Glory Kill. That way you can still use Glory Kills to tactically i-frame through attacks, but enemies have an opportunity to damage you before you’re able to dash away. I should note that most of what has been said about Glory Kills also applies to Chainsaw kills, as it’s basically executed in the same way. Chainsawing enemies would come off less “press C and watch a cutscene for free ammo” simple matter if there was a tangible risk attached to chainsawing enemies, as it would further encourage being aware of your surroundings and knowing when it’s safe to do a GK/Chainsaw.
One relevant change for Glory Kills is that your melee punch does next to no damage, meaning you can’t just walk up a Possessed and spam F for a free Glory Kill. What this means is that your primary way of setting up a Glory Kill is to shoot demons enough so they get staggered, but not that much so they get outright killed. So you have to control your shot count with the HAR if you wish to stagger fodder, or control at which you range you fire the Combat Shotgun. In practice, being this precise is easier said than done when you are at low health and being chased by several heavy demons. Having to shoot demons enough but not
too hard (if you want a Glory Kill) and your punches dealing piddly damage might sound counterintuitive in a franchise all about shooting demons, but it results in somewhat deeper gameplay than “mash F for a Glory Kill”.
The punch dealing no damage isn’t a major dealbreaker as dashing into enemies deals more damage; dash twice into a Possessed and they get staggered so you can Glory Kill them. They still could have made a punch deal as much damage as a dash though, since most people default to the punch for the melee and the game never tells you about ramming into enemies being an effective melee attack
The new Blood Punch mechanic is a good way of integrating a useful melee option in a shooter without it becoming too dominant or useless. It lets you deal massive burst damage against heavy demons, cancels summoned barriers from Carcasses and Archviles, can insta-kill Pinkies from the front, and punches 70% off of a Cyber-Mancubus’ health pool. It’s recharged by Glory Kills, so it provides an incentive to Glory Kill more aggressively by then letting you kill enemies more quickly with the Blood Punch, further pushing for an aggressive playstyle. What’s interesting is that the enemies which are weak to Blood Punch are also those that are specifically designed to keep you out of melee range, so you can’t just walk up to them and Blood Punch them without taking damage in the process--you need to set them up with a falter first. And Blood Punch being limited means you can’t spam it whenever.
The Weak Point system introduces several soft counters to enemies, allowing you to weaken them without outright killing them, in turn also facilitating switching between weapons that are more suitable for destroying Weak Points. For the Weak Points of Arachnotrons/Revenants/Mancubi/Makyr Drones, what weapon you want to use to destroy them depends on the situation. Sticky Bombs can be refired faster, are easier to land because of their larger size, but aren’t as viable at longer ranges because of their travel time and limited range. Precision Bolt is hitscan and so better suited for longer ranges, but it relying on a scope and having a lower RoF makes it less suitable at short-range unless you learn how to quickscope. The Ballista is suitable at any range and deals good damage on top of that, but its fire rate is very slow, and compared to other weapons it costs relatively more ammo. Alternatively, Heat Blast and Blood Punch are also very effective at destroying Weak Points in one shot without having to directly aim at it, but they need to be charged first.
This way each ammo type has a weapon you can use to dispose of Weak Points (except for Rockets, which can deal so much damage that they can just kill enemies without having to bother with their Weak Points), meaning you still have multiple valid options to deal with any given Weak Point. As another example, while the Shieldguy shields can be overloaded with the Plasma Rifle for an easy kill, so you can also circumvent their shields by: just Meathooking onto them (which forces them to put their shield aside and gives you extra armor in the process), firing any explosive behind their shields, using the Chaingun (which removes the shield just as fast as the Plasma Rifle but doesn’t make it explode), and taking out a Shieldguy from the front with a Destroyer Blade or firing at the slit in their shield with a Ballista/Precision Bolt. And even then there’s an opportunity cost to overloading the Shieldguy’s shield, where sometimes it’s a better idea to wait for them to only overload their shields when they’re in the middle of a group of enemies.
A problem arises when the soft counter is so powerful that using anything else is a waste of ammo, as is the case with the Cacodemon’s new grenade swallow weakness. Instead of wasting rockets on it, a single Sticky Bomb/Frag Grenade will lead to a free stagger (a single Arbalest will also be an one-shot kill). As the hitbox for shooting a nade in a Caco’s mouth and the hitbox for hitting a Caco with the Ballista are very large, exploiting this Weak Point is trivial. Doubly if you consider that Glory Killing a Caco is done in the air where other enemies can’t bodyblock you after it ends. The end result is that the Cacodemon is a boring enemy to fight because he’s high-priority (what with his highly damaging melee lunge and projectile burst), but easy to single out and take out. If it’s that easy to take out a high-priority target, why wouldn’t you? One could fix this by increasing the risk for the reward (f.e. the Caco can only swallow a nade when you fire at his mouth during his highly-damaging lunge attack), or decreasing the reward for the risk (f.e. swallowing a grenade only removes a third of the Caco’s health, meaning you have to commit to killing it with other weapons instead of waiting before it’s ready to swallow again, allowing the Caco to be a more effective pressure unit).
This bears extra mentioning:
Weak Points are soft counters, not hard counters. With the exception of the Maurader (and Cacodemon), you can kill any enemy with any weapon without having to exploit their Weak Points. But whether you can use those weapons also depends on the situation. Dread/Hell Knights and Barons of Hell can be consistently faltered with the Chaingun, but focusing on them with the Chaingun provides other enemies with an opening to attack you. Even though you can insta-kill Pinkies and punch off a Cyber-Mancubi’s armor with a Blood Punch, you can’t just safely walk up to them, you need to create a situation where that’s possible first. And once you learn how to switch cancel effectively or use the Lock-on Burst, you can kill most heavies without ever having to bother with their Weak Points to begin with, as destroying Weak Points doesn’t actually deal that much damage to their HP (aside from the Cyber-Mancubus). The Revenant is so weak that there’s no point in going after its Weak Points and it would take longer to kill it that way. At that point Weak Points are there when you want to disable one heavy when you want to focus on another one without getting interrupted, or when you want to falter a heavy. Focusing on Weak Points is definitely not required, and not even the most efficient strategy.
Despite this,
public opinion keeps persisting that Eternal has become a “puzzle shooter” where you must pull out this specific weapon against this specific enemy. It’s easy to point to the previous paragraphs and tell them to just git gud, but clearly somewhere something has gone somehow wrong in teaching the player that there’s more than one way to deal with most demons. For that, I’d point to Eternal’s tutorials, which has come to suffer from something I can only describe as overtutorialization. When the tutorials are so heavy-handed and tell you how to beat every new obstacle, it can happen that the player becomes trained to not to explore other options beyond what is shown (
one example being in this thread), because what
is shown is enough for them to survive most fights, and if it’s constantly rubbed into them through the loading tips, then it must be the most correct way to play, right? After all, why change up your winning strategy? The heavy-handedness of the tutorials and the constant reinforcement by loading tips can then give the impression that you must destroy Weak Points under any circumstance to not get killed by heavy demons, which is further reinforced by the first two-three levels of the game. At that point you don’t have the weapons/mods to quickly kill heavy demons with, so prioritizing Weak Points in those levels becomes very essential to your survival (especially against Cacodemons); a lesson which carries over to the rest of the game.
Even if the tutorials tell you about every single possible way to deal with a Weak Point, it doesn’t solve the core problem that players
feel forced to prioritize Weak Points, and that the game allows them to get away with doing so. It’s a similar problem as with the Cacodemon: it never really hurts to NOT exploit the Weak Points on Mancubi/Arachnotrons/Shieldguys. Briefly firing a quick Precision Bolt/Ballista shot or one/two Sticky Bombs is relatively low commitment for high rewards. The perceived reward and proven effectiveness taught in the early levels makes it always
seem worth it, and the game doesn’t consistently punish you for wrongly prioritizing it where you shouldn’t. Compare this to exploiting the Weak Points on the Knight-type enemies or Pinkies/Cyber-Mancubi, where whether you’re able to do so safely depends on the situation. If Eternal wishes itself to rid itself of this puzzle shooter criticism, it must present more drawbacks for trying to exploit any Weak Point. For example, if overloading a Shieldguy’s shield with the Plasma Rifle would also damage you if you got caught in its AoE, then you’d be much less inclined to use the Plasma Rifle up close, and instead consider if there’s a better weapon you can use up close or if you can afford to put some distance first between you and it. If disabling the Weak Points on a Revenant/Mancubus made it enter a kind of berserker mode (sort of how the Arachnotron will keep spamming grenades after you destroy its turret) that make them even more dangerous depending on the situation than if you were to keep their Weak Point alive, then there’d be another consideration to disabling the Weak Points.
As mentioned earlier, the tutorials are unusual even for AAA standards in how heavy-handed they are, going as far as telling you how to beat bosses. It might come off as patronizing, but if anything I appreciate it. Compare this to Platinum games where core mechanics that would improve your experience tenfold once you know about them are never mentioned or hidden in-game, forcing you to rely on third-party resources (like the freaking
developer blog) or hearsay to just learn about their existence. By just teaching you the rules, you can more quickly get to the “what can I do” to the “how can I do this” part, which is where the meat of the game lies. Especially for a FPS as unorthodox as Eternal, many of its mechanics are rather abstract and can’t be intuitively figured out (it can be deduced from all other games or just simple logic that fire enemies are weak to water attacks, but Knight-type enemies being weak to Chaingun or enemies having Blood Punch weaknesses isn’t), in which case just telling/showing the player about it or forcing them to experience it is the best option. The tutorials only told players through text about the essential fact that one pip of Chainsaw fuel always regenerates, yet I saw several comments of players who didn’t learn about this until halfway through the game, hence the necessity of forcing players to experience unorthodox mechanics like these. Either way, you can completely disable tutorials in the main menu, so you can choose to avoid being forced to deal with tutorials anyways.
There’s one important change that makes Eternal’s story infinitely better gameplay-wise than nuDoom’s, and that’s the ability to skip cutscenes. It means you no longer have to be locked in a room for 1-2 minutes doing nothing while forced to endure Dr. Hayden jabbering on about some plot junk. Unfortunately the story in Eternal jumped the shark in several ways compared to nuDoom, but that’s outside the scope of this post. There are still several 4-6 second unskippable mini-cutscenes after the end of battles that show a door or something opening, which are more tolerable, but still waste your time. So levels also have drawn-out elevator sequences for whatever reason where you can’t move for several seconds. While I’d like to say these could just be removed, it was recently brought to my attention that
AAA developers actually use long corridors and elevator rides to disguise loading screens. I suppose this fact is hidden from you to not break immersion, but I would be more accepting of these empty sequences if the game also showed you a LOADING… indicator on top of that. That, and making the elevator rides faster when loading has actually finished, for when you have an SSD for example.
The pacing of Eternal’s campaign is also massively improved over nuDoom. Where in nuDoom you only got your double jump in the fifth level, Eternal gives you your double jump and chainsaw right from the get-go, and it doles out weapons and mods and equipment at such a high pace that you’ll have most of your main tools by the fourth level in the game. It’s still not entirely ideal; the first two levels suck a lot compared to the rest of the campaign because you just don’t have most of your weapons and tools yet, meaning there isn’t much depth that can be had at that point of the game. The lack of depth in the first level can be excused since the player is still getting to grips with the game at this point, and it can be sped through by veterans. But the second level wastes too much time with jumping/environmental puzzles, and is a sore spot on replays. The Master Levels (remixed levels with tougher enemy placement) are a solution to this, although at the time of writing we only have two of these.
Speaking of the levels, it’s impossible not to mention the increased focus on platforming inbetween the arenas. It is more engaging than nuDoom’s empty corridors and incredibly basic jump-and-ledge-grab-over-the-gap platforming challenges, but it’s still not good. The core problem with the platforming in Eternal is still the same as nuDoom’s: it only challenges you on figuring out
where you need to go, not
how you go about getting there. Once you figured out where to go (which isn’t very hard considering Eternal heavily relies on the color green to signpost where you need to go next), that’s all there’s to it. As the execution for said routes is always incredibly lenient, there isn’t much replay value to be had. Segments that require you to dash over huge gaps using floating dash refills are always beatable with one dash or double jump remaining in stock. Platforms that fall when you stand on them/are attached to will take at least a second or two before they start falling. Most platforms and hazards do not move, ridding platforming challenges of the elements of timing and on-the-fly adjustment of landing on a moving platform you’re just about to miss. Platforming sections that require you to shoot a switch mid-air to temporarily open a gate are sadly rare. Sections that have hazards on the wall you’re climbing are also sadly rare. Being lenient isn’t a problem for the start of the game (because you’re still getting used to how the platforming works), but past the third level the platforming doesn’t demand any higher level of execution out of you or make you use your existing moveset in different ways, so the platforming quickly stops being exciting and feels more like filler (because it honestly is).
Screwing up platforming sections has also been made more lenient, as falling into a bottomless pit teleports you to the last piece of solid ground you stood on and takes a bit off your health, instead of being an instant death like in nuDoom. This change I actually appreciate, because it makes screwing up the platforming feel more fair. It’s a problem I have with a lot of shooters, where death in combat is often the result of several smaller mistakes adding up, yet the single mistake of missing a jump is always fatal, which feels like a disproportionate level of punishment. In older shooters everyone would always quicksave right before platforming sections because they were so fatal, so nobody cared about insta-death pits as much. But as nuDoom was checkpoint-based, you were forced to walk all the way over where you died. By teleporting you to the last piece of ground you stood on, Eternal manages to cut down on this downtime and get you back to the meat of the exciting platforming.
Another thing that seems like wasted potential to me is that the platforming elements are almost entirely separated from the combat arenas. There are rarely ever enemies threatening you while you’re wall climbing or swinging between monkey bars or jumping from platforms, and the heavier platforming elements are never featured in the combat arenas themselves. It would have been interesting to have a few gimmick arenas where there’s barely any solid ground to stand on, and you’re forced to stay in the air using wall climbing, monkey bars, and your Meathook. If anything, not having the Meathook be utilized for the platforming itself is also a huge waste considering the opportunities it already provides
One thing that gets brought up rather often (despite only appearing in two levels of the game) is the purple goo. When you’re standing in it, you’re slowed down and can’t jump or dash. The problem with it is that in Exultia the level
forces you to wade through it. You have no options to speed things up (aside from using the level geometry in unintended ways to skip the purple goo altogether, which isn’t applicable everywhere), which makes these unexciting, especially on replays. And combat-wise all you’re doing here is playing whack-a-mole with Tentacles, which doesn’t come close to the depth offered by regular combat. While filler segments are necessary to prevent players from having to stop playing and take a break, these segments go all the way into “turn your brain off” territory.
However, I still believe that purple goo can be good if used as an environmental hazard, instead of forcing the player to move in it. The first outdoor arena in ARC Complex is a good example, as it forces you to get more creative with the surfaces in the arena that aren’t covered in purple goo (but are covered with enemies), and so punishes sloppy movement/positioning if you fall into the goo. It is only a shame that purple goo is rarely used at all (in this way). Another thing to consider is that, while almost all your movement options are restricted in purple goo,
pulling yourself out of the goo with the Meathook isn’t. Knowing this, it would have made infinitely more sense to only introduce the purple goo right after the player gets the Super Shotgun + Meathook, and so place them in an environment filled with purple goo where they’re forced to make use of this new tool in order to survive.
Arenas in Eternal tend to feature more gimmicks than in nuDoom, which I think is very useful for arena level design, though I have to make a big detour to explain why.
One of the core tenets of olDoom is that it’s about fighting for breathing space. While you are the fastest entity in the game, enemies have large hitboxes and often come in large numbers, which combined with constrictive level layouts, hitscan enemies, and infinitely tall enemy hitboxes/a lack of vertical mobility options, means that running past enemies often isn’t an option. As enemies keep encroaching you on what little free space you have, you will eventually get overwhelmed.
Compared to olDoom, both the player and enemies in nuDoom/Eternal have way more mobility. This mobility allows the battlefield to keep shifting unpredictably, forcing you to keep repositioning and improvising your strategy on the fly. A single encounter can then play out in many different ways, but if every encounter is an unpredictable improvisation-fest with no elements to distinguish them from one another, then they’ll start blurring together. Normally these distinct elements are realized through the level layout/enemy placement, but here nuDoom/Eternal runs into another problem:
the level designer cannot predict where exactly the enemy will decide to move. In exchange for letting the enemies move however they like and let the AI create the challenge, the level designer forfeits a degree of control in designing levels. In order to allow the AI to utilize its movement options meaningfully (a Whiplash or Prowler is wasted when put in a monster closet or narrow corridor), all arenas must be designed with a set of guidelines (or restrictions), which is why almost all arenas in Eternal have this circular open ‘skatepark’ design, as it provides both the enemy and the player enough space to keep outmaneuvering eachother. However, most of these skatepark layouts by themselves don’t make you play all that differently compared to others, and you can get away with the same strategy of “run circles around the edges of the arena while only diving in for resources” on most of them, so rarely are these skateparks a driving force in making you reconsider your general strategy..
Games with simple and predictable enemies, like in olDoom and Super Mario Bros, give the designer way more control over how and where they can be used. As fighting an enemy with simple AI isn’t that interesting by itself, the level design needs to compensate for it through the enemy placement or level layout. Here the level layout strongly affects how an encounter plays out, as simple enemies are way more reliant on the level layout to pose a threat. This opens up way more level design possibilities compared to games where more complex enemies place restrictions on how they can be used effectively, and this greater freedom allowed for greatly unique levels where the layout dictates your approach instead of the AI. The Mario games and olDoom have an incredible amount of custom levels made for them, whereas something like Devil May Cry doesn’t lend itself well to custom levels. There the only thing you can change about each encounter is which enemies get used, how many of them there are, and where they spawn, as the layout of the arena barely affects the combat and enemy behaviour. The total amount of level design possibilities here are limited by only the total amount of enemy combinations, which doesn’t even come close to that of Super Mario Bros. or olDoom.
The arena layout does affect combat/enemy behaviour in Eternal, but not always to a degree to make it stand out from others. In nuDoom, the game tried to keep things fresh by padding out the rate at which you were introduced to new weapons and new enemies, but as it ran out of new enemies/weapons, so did its final levels start to blur together, because there was nothing new or fundamentally different about them. Another option is to introduce some kind of gimmick that fundamentally forces the player to change their approach. This can range from environmental interactables like traps and crushers you can trigger, to environmental hazards like purple goo, damaging floors, or platforms that fall when you step on them. A better example of this is
DESYNC’s Aberration Zones, which are remixed versions of existing levels that periodically apply new mutators that make the game easier or harder (such as ‘all enemies explode on death’, and ‘you can dual-wield weapons’) and stack on top of eachother, forcing the player to adapt to a new playstyle and use existing mechanics in a way they normally wouldn’t have much reason to. The gist here is that gimmicks like these can be added without interfering with the enemy AI/placement, or even with the arena layout, and so be used to more easily increase the amount of ‘unique’ arenas.
That is not to say gimmicks are necessary for arena level design. In fact, Eternal already has an effective solution to this problem. Instead of just introducing new content, it creates memorable situations by constantly upping the ante in complexity. Arenas that pose new and more challenging enemy combinations compared to what came before stand out because the player has to rethink how to up their ante again if they want to survive, of which the extra-challenging Slayer Gates are a great example.
Keeping a smooth difficulty curve is important here; if the difficulty doesn’t rise fast enough then it feels like there’s too much filler, and if the difficulty spikes too early, then what comes after feels boring unless the highs get even higher. However, difficulty by itself isn’t the core factor here. If you ask people who play on Ultra-Nightmare, the hardest level in the game would be the 2nd/3rd one, since you don’t have most of your upgrades/tools at that point yet. But the game still remains interesting even after, because the enemy formations get more complex as the game goes on, asking of you to make even better use of your toolset. Here difficulty is merely a byproduct; it exists to create a wall that blocks progress, and force the player to learn how to use the tools given to them to scale it. Without difficulty, there is no reason to fully utilize your toolset if anything you do will pass for success. The end goal is to get the player to learn and interact the system to the deepest extent possible, but depth and difficulty aren’t necessarily inseparable. Even though Eternal is undoubtedly deeper (and therefore more engaging) than nuDoom, I would still say it’s easier since you have more tools to keep yourself alive with, and no Imps sniping you for 45HP, for one.
nuDoom failed at keeping things interesting because of its broken weapon balance that would make even the harder encounters in the game a total breeze, and even then it took the game ages to get going with its enemy combinations (because it was trying to pad out new content as much as possible), where Barons of Hell only appeared rarely, and usually by their own at that. Eternal instead excels at this by introducing its cast at a much faster pace than nuDoom, having a large enough cast to allow for a large variety of enemy combinations to begin with, while also providing a sneak peek for higher-level enemies in the early-game through its optional Slayer Gates. On top of that, Eternal also has Master Levels, which remixes existing levels to feature even more dangerous combinations of high-level enemies, keeping things interesting for players who want to push the boundaries of the gameplay even further. id Software
also mentioned in a talk that future Master Levels might even feature some of the aforementioned gimmicks, such as Superman 64 Fog, but for that we still have to see.
The upgrade system is still here, and still vapid as ever. As usual, you get enough upgrade points by the 2/3rd point of the game to upgrade everything useful, which kills any semblance of build variety and makes your upgrade choices stop mattering near the end. Most of the Fundamentals Suit Upgrades should’ve been just applied from the start since there’s no reason to not take them, as they allow for more options in terms of weapon switching combos and mobility. The Frag Grenade isn’t all that useful until you upgrade it and some Weapon Mods aren’t really worth using until upgraded (such as Destroyer Blade, Remote Detonation, Mobile Turret), so those upgrades might have as well been applied from the start too. You still need to do challenges to unlock weapon masteries, which limits your freedom in combat by keeping useful upgrades hostage until you kill particular enemies in this particular way. It is telling how shallow this system is that Eternal now offers Mastery Tokens which just lets you skip weapon mastery challenges altogether.
One area that has been improved on are the Runes. Instead of locking specific Runes to specific Rune Trials which appear once in the entire campaign, each Rune Station in Eternal lets you pick one of the available nine Runes in any order you like. This means that you do not have to wait until half the game to get Mid-Air Control, and can just get Runes that suit your playstyle from the get-go. The new Chrono Strike rune just gives you slow-mo, and might be considered rather OP because of it. Normally I hate broken tools being defended with "just don't use it" (because most players don't even consider playing with self-imposed restrictions and so might unintentionally and unknowingly ruin the game for themselves), but here the limited amount of Runes you can equip actually gives you a valid reason not to use Chrono Strike. Personally I want to go as fast as possible, and having to sacrifice Faster GKs/Air Control/Blood Fueled for Chrono Strike would not be worth the trade-off. Even then the slo-mo gets more in the way than anything because you can't avoid activating it when using your alt. fire mid-air. So there's people who prefer not using the Faster GKs rune because they like having the extra breather in combat to decide on their next course of action. So limiting the degree to which you can customize the playstyle of your character acts as a legitimate incentive to not use the most broken configuration at your disposal, as seen in RPGs about designing unique builds. You can always find a build that breaks the entire game, but there's still plenty of other possible builds with unique playstyles that may be more appealing to you even if they're not the most efficient.
All the weapons and weapon mods have been substantially overhauled to be worth using more, at least on paper. Like D16, the Super Shotgun and Gauss Cannon (now known as the Ballista) are still your main pillars because of the DPS you get off switch canceling them and the newfound utility of the (Flaming) Meathook, but unlike D16 all the other weapons have more defined niches to make them regularly worth using even when discounting the decreased max ammo caps.
The Combat Shotgun primary fire is still mostly useless once you get the Sticky Bomb mod 2 minutes into the game. With the removal of the infinite-ammo Pistol, the shotgun primary fire could have as well served a role as infinite-ammo fallback since now it only has a very small niche (setting up fodder for GKs, which the HAR does a more consistent job at anyways) in a full arsenal. The Sticky Bomb now fires three/five explosives that one-shots fodder and destroys Weak Points compared to the single-shot Explosive Shot in D16, which makes sense considering how many more fodder and Weak Points (and especially Cacodemons) Eternal throws at you.
The Auto-Fire serves to replace the useless Charged Burst, but it’s still never truly worth using. It must be deployed before firing, it slows you down when deployed, it has only a short effective range on account of being a shotgun, it chews through all your ammo, and worst of all, the DPS does not make up for it. Compare this to the Chaingun’s Mobile Turret which serves a similar purpose (sustained DPS at the cost of your mobility and a lot of your ammo), but doesn’t slow you down as much, deals equivalent DPS, has more ammo to chew through, and is effective on most ranges. The Auto-Fire simply cannot compete. As the Auto-Fire is inherently the riskiest to use because of its short range, the only way to make it truly worthwhile to use is to give it the best DPS in the game and/or reduce/remove the mobility penalty and/or deployment time. To increase its range would just make it a Mobile Turret clone, which is redundant. The upgrade for the Auto-Fire that makes enemies drop shotgun shells on death does make it worth using, but other options are just better.
The Plasma Rifle may no longer have its OP Stun Bomb, but it’s still worth using for other reasons. Its primary fire now makes enemies explode on death, making it useful for groups of fodder, and it can also make quick work of Shieldguys by overloading their shield. The new Heat Blast, when fully charged, works like a pocket Blood Punch with bigger range. Its crowd control/Weak Point disabling is very useful, and so provides another reason to use the primary fire to keep it charged.
On the other hand, the Microwave Beam is pretty bad at its intended role. It makes you completely commit to one enemy by locking your aim on them and making you move at a snail’s pace in a game where you’re always outnumbered and surrounded. Its DPS is simply not worth the risk of using it, even with its increase in the latest update. Killing heavier demons with it damages all nearby enemies in a ridiculous AoE, so ideally you want to reduce a demon’s health to almost zero and reduce the amount of time you spend moving slowly while locked on. But the strangest thing is that locking onto a staggered demon cancels their stagger state and instantly resets their health from 10-20% to 50% (like what usually happens if you don’t finish off a staggered demon fast enough). So you have to stay locked-on to an enemy for several seconds in order to trigger an explosion on death, making the Microwave Beam much less viable to use than it could have been if it only took 1-2 seconds to microwave staggered enemies. Arguably there is a higher skill ceiling to knowing how much you can damage an enemy without staggering it so you can minimize the time spent on microwaving it, but this higher execution barrier just ends up making it less relevant compared to other options. The Microwave Beam does have a niche where it’s able to falter any enemy with a quick tap of the beam, so you can briefly fire the beam for one tick to falter them, and then immediately combo with another weapon to deal damage while they’re immobile. You can’t stack the falter with other weapons like you can with Frags, but unlike Frags the Beam is not limited to cooldown charges.
The HAR (now the Heavy Cannon, but whatever) in nuDoom became less useful as the game went on, but in Eternal it still has some good niches for its ability to set up GKs, and the usefulness of its revamped Scope mod (now the Precision Bolt). Whereas in nuDoom it was just a useless zoom that did a bit more damage on headshots, the Precision Bolt can quickly fires a penetrative single shot that can take out multiple fodder enemies in one hit, and more importantly it can also one-shot Weak Points from any range. The fact that the Precision Bolt is semi-automatic now means that quickly switching to and fro the Precision Bolt to quickscope something makes it attractive to incorporate into your weapon combos.
The same can’t be said for the Micro-Missiles mod. While it still has a useful niche (outputting damage equivalent to the Mobile Turret without the mobility penalty, but with increased ammo consumption), the Precision Bolt is a way more versatile mod, which means you generally want to keep that mod selected. Switching mods to the Micro-Missiles means being briefly unable to fire and losing out on being immediately able to use the more versatile Precision Bolt, meaning that you will likely have to switch mods again back to the Precision Bolt.
The fact that you can only have one mod equipped at once greatly biases your choice towards more versatile mods that cover more use cases than the other mod, and so require you to switch less often. Meanwhile the more situational mods are hidden by another layer of commitment (switching mods) that doesn’t always seem to be worth the trade-off. This would be more acceptable if both mods for a weapon were perfectly balanced, but it’s impossible to balance a mod’s power around having to switch twice to it, when you can have said mod equipped from the start and just switch to it once. Instead of doing a weapon switch and then a mod switch, it’s faster to switch once to another weapon that shares a similar use case. Instead of firing a Destroyer Blade, a remote detonated rocket has a similar effect. As it stands, mods like the Micro-Missiles, Auto-Fire and Destroyer Blade, lose out in this system. If mod switching was instant, then this wouldn’t be as much of a problem. Even better would be to repurpose the two mods for each weapon as a secondary and tertiary fire and remove the input barrier completely, and so allow for potentially more interesting synergies between your three modes of fire that wouldn’t be possible with the old system (although this might be a hassle on a gamepad layout).