shmups.system11.org

After a suitable while of cogitation, mulling, reflection and gnawing doubts, here's my attempt at a difficulty list for classic shooters. I've also tossed in the few aberrant shooters I've cleared so that you can compare them with all the other games. This list is obviously inspired by the Japanese wiki, thus I used the same grades. I want to thank vvv_stg for coming up with this neat format, I think it makes for a pleasant reading experience. A few notes before we start:

- Only games I've cleared on a single credit myself. All of these were played on the default settings (difficulty/extends) with the exception of autofire (see next paragraph). I will add more games as/when/if I clear them.

- Every game was played with autofire if/when it was beneficial, I directly priced that into the ratings. This also means using some 30hz in, say Darius Gaiden or Area 88. I believe I've used a less-than-optimal rate in U.S. Navy, but that doesn't matter much in any case. You'd also be wise to not set up your autofire too high for Twin Eagle lest you might find yourself in an interesting situation...

- Those rankings reflect survival. Now, in most of these games, survival and scoring goes hand in hand (unless we're talking about checkpoint milking). But there are a few cases where it could make a palpable difference. Survival play doesn't necessarily include taking extreme measures. Most notably, Gokujou Parodius can be kept at minimum rank at all times if you take special preparations (suiciding, constantly activating the "OMG" field, avoiding every bell to keep the score low). That's not what I have in mind; if you have to drop a bell chain for survival or hold back on a few upgrades then that's fine.

- I tried to incorporate player sides, characters and version differences whenever I was aware of them. Since I haven't played every single game with every character, those notes can be a bit vague at times. I also probably forgot some things.

- It should be explicitly noticed that this is merely my own personal experience. I am thankful when you guys chime in to agree, disagree and generally give your own thoughts on it for you probably have different strengths and weaknesses. I find methodical games with heaps of memorization and less execution to be tendentially easier than those with really fast bullets. Someone else might have a lot of problems with terrain-infiltrated horizontals and comparatively little trouble with frantic verticals. I'm also not adamant about a couple of points here and there. A 25 rating could probably be just as well a 24, a 26 or a 23.

- I couldn't use some of the special characters due to the formatting, hence "Galaga 88" instead of Galaga '88, no "Revenge Joe's Brother" after "Twin Eagle", Asuka + Asuka as opposed to Asuka & Asuka etc.

That's enough for the preface. Here's the list:





Edit for 16-bit games!

- I specify the difficulty if the game happens to start on something other than Normal. I always have internal autofire in mind (even if it is turned off by default), for the PCE even external autofire. I mention it where it matters on the SFC/MD. For everything else, see above (especially for the part about formatting, I really didn't want to call the game "Popn TwinBee", for example...)





Another edit for NES/Famicom games!

- Same applies as with 16-bit games, except for the fact that external autofire is considered whenever beneficial and unless noted otherwise.

Few things I disagree on:
- Master of Weapon is nowhere near that hard, you just have to get drunk and ignore the background. I'd drop it at least 6 points, probably more.
- Mad Shark can probably drop 2 points, it's definitely not harder than FixEight at least.
- Would maybe drop USAAF Mustang 2 points or more, since it's so trivial until the last stage. Maybe that's why it's where it's at though
- Tiger-Heli I'd drop 2 or 3 points, the difficulty is mostly not falling asleep or ripping your ears out from the power up music.
- Omega Fighter could probably stand a few points higher, it's much harder than DonPachi 1-ALL bombspam clear.
- Would either drop Gunnail down a point, or raise Rapid Hero up a point, leaning towards the latter.
- Sand Scorpion up one point.

And an addition of "secondary" setting:
- Thunder Dragon 2 on 1P side is probably -3

Overall mostly agree, very nice list and good to see your rankings finally!

Cool list, some thoughts:

-Raiden: I would remark that it's the no checkpoints version, since the one with checkpoints is probably as difficult as Raiden 2/DX.
-I feel like TD2 should be like 3 points lower, Gradius III is an exhaustingly long game that requires tons of strategizing from stage 3 onwards, while TD2 doesn't get that difficult until the last 2 or 3 stages.
-Star Force should be in the early 30s for me, I found it quite vicious but maybe I'm just terrible at it.
-Scramble: I would add that multilooping it would be like +10 points, the game reaches max difficulty at loop 3 or 4 and even then it's easy to master (I cleared 10 loops without much practice), the only difficult part is that you only get one extend.
-I remember Baron Rojo told me that Thunder Dragon was easier to clear than TD2, mainly because the extends help a lot.
-Hishouzame reaches max difficulty at loop 4?
-Funny how much Sengoku Blade dropped, 24 points definitely was inappropriate although I'd put it on par with Strikers and Gunbird.
-For Twin Cobra I'd say that it's more like -10 (similar in difficulty to Hishouzame), the game gives you so many extends that if you are able to reach stage 6 or 7 without dying the rest is trivial. Also when you die on a boss the game pretty much kills it for you.

Really good stuff!

But Gradius III more difficult than IV? That's the first time I hear about such a view.

And a question: where would you rank Hacha Mecha Fighters? Would be cool if you try it out if you haven't already.

The first loop definitely is, ivs difficulty is massively overrated because most people in the west quit a game within 3 hrs before they understand how it works on any level. Iv's a very fair game until loop 3 then it's dirt sandwich all the way.

Well, nothing is worse than the cube rush, so you've got a point there.

the higher numbers seem pretty inflated on the whole but the thing that just stuns me is this:

gun.smoke is even with bee storm

maybe this is just me, but bee storm is not a hard 1cc bya ny means, and gun.smoke is hands down one of the hardest to beat shmups i have played, i would put it up there as high as tatsujin ou which is mildly overrated. ofc if noone else finds gunsmoke hard then im just weird i guess. there are some other things i would change around as well, strikers 1-alls are easy for example (why is ii so much higher than 1?)

it might be hard to get much community input here but that's my 2c at least.

BTW what counts as classic? seems like there's some stuff missing here (if bee storm can pass as classic then + more psikyos, garegga, and more, which should be easy enough to get input on)

First of all many thanks for all the input! I'll add a few notes later (such as the no checkpoint version regarding Raiden etc.) and might think about a handful of ratings. As for a few points (and I want to expliclity point out that when I'm "disagreeing", I'm merely trying to describe how I perceive things, I'm not "denying" any of your arguments!):


That's one of those games I find indeed hard to place. On one hand, it is not quite as consistently hard as Raiden II or DX. However, it is the only tough vertical in that difficulty range where you don't get any bombs at all (the one-time bomb sub-weapon doesn't count). You'll have to survive everything just by dodging the entire time, no panic button or anything. Combine that with the bullet wobble and the fact that deaths can be extremely punishing (I don't think you can really beat the final boss without at least a few power-ups or at least not easily) and you end up with a brutal game.



Really? The checkpoints themselves aren't that important since you want to beat the game on your first life in any case, so I'm going to assume that the difficulty of the Japanese version is just so much higher (by means of bullet speed etc.)? I should check that out for sure!


I'll add something along those lines, I've cleared a bunch of loops myself but wasn't sure just how/when the difficulty is at its highest.


I'm a bit mystified by the first Thunder Dragon to be honest. On top of the general problems with it (colossal hitbox, visibility, some cheap tricks) there're also some occurrences I haven't figured out (yet). For example, it seems like only the first extend is guaranteed, the others may or may not appear. I've also seen in Baron Rojo's replay that he was able to just hug the lower borders of the screen to take out the incoming popcorn enemies in the final level, when I do that in my savestate I just get shot in the face from enemies that aren't even on-screen at that point. Maybe it has to do with rank or some other factor.



Yes, certainly. IV has a few spots that are arguably tougher than their equivalents in III (crystal/bubble stage, moai stage, cell stage), but due to the dynamic rank you're always able to recover from every spot in the game without extreme prior knowledge. A death in III in the wrong spot is an instant game over if you don't have the necessary arcane knowledge - and for all intents and purposes you're better off starting a new credit and playing for as long as it takes to get past tricky spots instead of learning those checkpoint recoveries which would take much longer. III is also about twice as long as IV (depending on how many times you die on the cube rush) and has a tendency to sap away your concentration by the time you reach the dangerous final stage. It additionally has nasty bouts of slowdown that love to subside all of a sudden, thus tossing unaware players into walls and whatnot.


Haven't played much of it, but from what little I've actually experienced and watched via videos it has to be way up there. When I'm feeling brave enough I'll took a closer look.



Feel free to point out other examples if you have anything specific in mind. It's always good to have more input from an expert player such as yourself! What games (in general, not just from the ones I've listed) would you put in the highest spots (say, from 36-45)?


I'm decidedly terrible at anything bullet hell, that's why Bee Storm is so high up there. Gun.Smoke is overall a tough game, but there's not much of a penalty to dying. You also earn many extends which furthermore eases the pressure. The margin of error is just overall considerably bigger which is not the case in most games above it. I will say that the final boss is a veritable jerk, though.


I'm also quite horrendous at Psikyo. II has a lot more fast bullets and patterns than the first one or so I find. I had not much of a problem memorizing safe routes for the first Strikers while the second one threw me off quite a bit.


I've just added what little I've played of Psikyo and those DDP games to have a contrast to the other, mostly "classic", games. I'm very interested to hear how seasoned Cave/Psikyo/Raizing/... players would fit in those respective games in a comprehensive list. Maybe we should create another thread where we compile a list with all the arcade games together, as a community project? That way, particularly high/low numbers might get corrected by others, creating a more balanced list overall.

Great thread, as is to be expected from Perikles.

I am woefully inexperienced on the STG 1CC front, but feel like adding my 2c on Gun.Smoke, one of my few 1CCs listed (along with the formidable Thunder Cross ). In addition to Perikles' point on its surprising generosity with resources, it's quite idiosyncratic among "traditional" STGs. Both its strafing system, and the intense focus on short-ranged duelling with lethally persistent zako. My gaming history is more in run n' guns/topdown shooting ala Commando, so I took to the strafing and ground combat quite quickly... and I distinctly remember the game really breaking open once I got inside the head of its mainstay "Grey" enemy. This is all very specialised skill, though - I still get my blackened, disintegrating buttocks hurled back in my face by things like Gradius III and Image Fight.

So I'm not surprised to hear a more accomplished player like chum might find it tougher than someone like me, who's spent a lot of time adapting to this one specific, slightly oddball title.

Metal Black is noticeably similar in regards to idiosyncrasy and deceptive generosity, I think - though I must stress, I'd rate its innate toughness nowhere near Gun.Smoke's.

all right, maybe I'm making too much of gun.smoke. let's call that a personal struggle. (getting past stage 6 urgh...)



i'm sure you are aware there is nobody else on this forum with anywhere near as much experience/understanding as you have across all these arcade games. so keep in mind this is only my opinion. i think tatsujin ou and zing zing zip at the very least are a bit overrated here. you also admitted that you struggle with the more bullet hell variety shmups which explains why some games are a bit high to me like bee storm and strikers ii. IMO you shouldn't change anything and just leave this list as your own personal opinion. then if we want to as a community we can try to make our own list if we want. the problem with this obvious though: very few people have sufficient experience on the higher games. that other japanese list would be helpful, though. personally i have not beaten a harder game than gunbird 2 and there's definitely still harder stuff than that like daioujou (white label) and... i guess detana twinbee!?!? had no idea that game was that tough in the 2nd loop but i'll take your word for it. hacha mecha fighter 2nd loop must surely be harder than daioujou though, unless some magician shows me how the hell that is supposed to be done in the later half (some exploit?)

i would give gunbird 2 something in mid-high 30s range BTW.

and is S!S!S! really that hard? not just unforgiving, but flat out THAT hard? O_o gotta play that more some time...

Tough bosses in Gun.Smoke is the main obstacle imo.

I could get to the stage 6 boss every time (many, many times) but I only ever beat him about 3 times.

I do feel it's a bit overrated, but it's a few notches above Raiden II at least. Once you hit stage 5, the gauntlet's thrown and it's ready to fuck you up the ass.

Checkpoint recovery is almost completely impossible after stage 2 or so, best you'll do is limp along an additional stage with your 12 stocked up extra lives. Lightning fast bullets -- even faster than Raiden II generally -- and lots of cheap tricks as well as fast moving highly aggressive zakos, it's a game intentionally designed to be one of the hardest of the hard. And that's why I love it

Great list, love this sort of thing. At a glance the only things I'd see I'd adjust:

* Batsugun Special 1-ALL would be down at a 3 or 2. I find it's unbelievably easy thanks to the smaller hitbox, shield power, and much beefier bomb (it's the 2-player combo attack bomb from the original game). Regardless of ship you're using, I'd say it's easier than a Raiga: Strato Fighter 1st loop clear. Raiga isn't a super difficult game, but recovery can be pretty nasty if you make a mistake since you're pretty seriously depowered.

* 2-ALL clear of Raiga would be up at 14 or so. I find the original Batsugun and DonPachi generally more manageable thanks to the bombs, whereas Raiga is really long. You can stock a bunch of lives in Raiga, but one death can lead to multi-life chain deaths due to how depowered you are. If you just want a DonPachi 1-ALL or Batsugun clear, good use of bombs help make those a bit easier than Raiga, at least as far as I felt.

I haven't cleared anything higher than a 14 on this ;___; Did do pretty well towards working towards a Salamander 2-ALL (which is unbelievably nasty with rank, as well as in the second loop) and reached the TLB of DDP II: BS (not quite cleared it yet). This is a really impressive list of game clears!

Can you give some more details on why you feel Twin Hawk is a decent amount harder than Daisenpu? Usually with the overseas Toaplan versions where checkpoints are removed, they are considered easier.



Yes, it's fucking brutal. Even on the easiest dips, and using Trap's hack for better speed and insta-power-ups, I can't seem to get past stage 3. The bullets are way too fast, even at that early point in the game (there are 10 stages). Fire Shark has a much gentler difficulty curve but it still gets to mayhem levels stages 5 and beyond.

It's unbelievable that you've cleared 400 games now!!!

The only one I really disagree on is Raiden, although I guess you played the US version without checkpoints? The Japanese version is basically a 1 life game, where none of the checkpoints are recoverable. Hell, I'd argue that the checkpoints in Raiden are worse than those in Gradius III. Raiden is a 28 or 29 to me.

Also, in the US version, when you die fully powered you get a free P powerup (in addition to not having checkpoints), which makes a massive difference IMO. Sure, if you can 1 life the game they are basically equivalent, but a run with deaths is at least possible in the US version while it just isn't in the Japanese version.

Overall, an awesome and impressive list of games, thanks for taking the time and doing this, it's such a great resource!

Keyword usually, Twin Hawk removes the checkpoints but it adds awful damage sponge enemies everywhere, Daisenpuu is overall a fairer game and the checkpoints are pretty recoverable (like most Toaplan games)

Did you play 1942 or the original 1943? Where would you place them if you 1cc'ed them?

agreed

First of all and again thank you for all your input! I find it not only highly interesting to read, but also rewarding to see how some views differ. A few things have been added:

- Some minor corrections/standardizations regarding spelling (e.g. the game's called Forgotten Worlds, not "Forgotten World" ).

- I suppose that should be obvious, but I also added another note in the preamble that these values concern the default settings. This should be normal difficulty or the equivalent thereof for almost every game unless noted otherwise, one noteworthy exception would be Star Force which is set to the easiest difficulty - the normal mode in that one is downright silly.

- Added a note for the version in Raiden as well as looping in Scramble.

- Three new games: Finalizer: Super Transformation (12), Thunder Dragon (32) and Valtric (27). Turns out that Valtric is merely tough if you know how to turn the sprite limit against the final boss, without that trick it would indeed be extremely hard (probably what the Japanese wiki intended). The first Thunder Dragon I do find harder than the second, it fits very well with its awkward brethrens Master of Weapon and Zing Zing Zip. Finalizer is one of the most bizarre - and worst - games I've ever played, more on that in alio loco.

- Also came up with another speculative goal: a full Raiden DX clear, starting from the training course, all the way through one loop. You have to qualify in training first (which means you have to play really well), starting from 1-1 you effectively enter the second loop in terms of difficulty, and from 1-6 onwards it's loop 3 difficulty. That would qualify as one of the hardest clears out there within the classic realm.

________


It doesn't look hard at all, but due to the laughable hitboxes you simply can't survive the suicide bullets since the game is clearly not designed for these. That means that you have to perfectly counter every single little enemy with the shippo barriers that can neutralize bullets, yet move around in an incredibly awkward pattern. It's the ultimate test of dedication, patience and routing since you cannot handle a damn thing on reaction. There're also additional enemies on top of everything else to add insult to injury. Dying once is an instant game over.



As mentioned above, I added a note for Raiden. The only time I've cleared the game (indeed one of the Western versions without checkpoints) was on my first life, so I certainly had that in mind when creating that entry on the list. Maybe the Japanese version is also simply harder in addition to the checkpoints? I'm going to check that out eventually!


Precisely. Twin Hawk's larger enemies and bosses take an absurd amount of damage, even with autofire you're not going to kill the battle cruisers unless you're at full power and constantly point-blanking. That easily leads to unavoidable concatenations of deaths that are simply not present in Daisenpuu where you die once and then merrily proceed.


I have played a little bit of 1942, but next to nothing of the original 1943. I don't know how much of a factor the final boss in 1942 is (especially with autofire), but I would guess it would land somewhere in the 23-26 range, that might be very wrong, though. I have the impression that it's slightly above average in terms of overall difficulty, but it is excessively long and (in my opinion) mind-numbingly boring which results in credits just melting away after a while.

I feel like V-V is way too high on the list.
I might be biased since tons of people during STGT'12 managed to 2-ALL that in a week.
Myself and three other people even perfect no-missed 2-ALL'd it.
The 1st loop at some point almost managed to put me to sleep and the 2nd loop really isn't that bad.
Sure it has suicide bullets but they are super wimpy in terms of suicide bullets.
There is also tons of room for error since you get shields, which means you can take a million hits and still clear.

Also yeah DDP2 is waaaaay and waaaaay too high. It's not a hard game by any means and it's super cheezable.

Nice list! I think Darius Gaiden's rather high up for how easy it is with autofire, and maybe TwinBee (half the difficulty in that game's first loop is simply learning how to power up at the start). I also find Strikers 1945 II easier than Strikers 1945 (if only because the stage order is fixed on startup and there's less input lag in MAME), and Gunbird also easier than Strikers 1945 (though that's with Marion). Other than that I largely agree with this list (though I haven't cleared the vast majority of these games).

Where do you reckon a Gradius III 2-ALL would fall?

It's really interesting to see a list from one person, where the difficulty ratings are all from the same scale. I'll be looking to this list for ideas on future 1cc attempts.

I haven't cleared anything ranked at 20+, so in those rarefied realms I can't offer any informed opinions on rank ordering, just admiration.

Our arcade 1cc lists have about 18 games in the intersection, and generally I'd rank things in about the same difficulty range (plus or minus one or two). Most of the differences can probably be chalked to differences in personal taste and style, and maybe me mis-remembering the difficulty of games I cleared years ago.
- I play without autofire, and I think that explains some of the differences - for instance, I had a bit more trouble with both Fire Barrel and Fantasy Zone.
- I saw a couple of entries that surprised me with how high they were ranked, Ultimate Ecology and Sonic Wings 2. In both cases I played the US version (Eco Fighters / Aero Fighters 2), so I'll bet there could be version differences that explain why I rank them lower. Or, maybe it comes down to differences in routing - both of those games permit some cheesy low-risk tactics. (I'd put Eco fighters at a 14 or so, Aero Fighters 2 around a 12).

Maybe I'm mistaking 1943 Kai for regular 1943, but it seems to be too high on the list when all that game is about is keeping the shotgun going? Above Darius Gaiden and DoDonpachi? I find those two games harder. Way harder.

And I do still think it would be a great idea to create something in this vein as a community project - we might not get that many opinions on some obscure games, but probably for most of them. I actually feel a bit bad about not changing things accordingly...



I would imagine that both games are much easier for someone as prodigious as you are at this sort of game (genre, really). That's not meant as a feeble defense, I actually agree that my DDP2 rating in particular is really more of a reflection of how bad I am at it and games like it.


I will say in this instance, however, that I always see the achievements during past STGT's moreso as a proof of how many skilled players use(d) to participate. During that same STGT, there were also 8 Strikers 1999 2-ALLs - and I would imagine that most people wouldn't consider any Psikyo 2-ALL that is not Sengoku Ace to be easy at all.



From my futile savestate attempts at getting any consistency at it, I would definitely say it is harder than every game I have cleared so far. Probably not as hard as a Parodius Da! 2-ALL, so I would assume a 43 or so. The game and its penchant for wayward slowdowns was clearly not designed for suicide bullets, let's not even speak about the bubble stage...



I do know that there are version differences between the first Sonic Wings/Aero Fighters (more than anyone could count in that case) and I've read that apparently, the European version of Sonic Wings 3 is harder than other sets, so it wouldn't be surprised about Sonic Wings 2, either, although I'm not sure.



Maybe I overlooked something, but while the shotgun neutralizes shots, it does pitiful damage against bosses and larger enemies which is why I switched to the laser for those. This added a bit of tension/risk of dying, making it a tiny bit harder than Darius Gaiden and DDP that allow you to bomb away.

Strikers 99 isn't too bad and compared to some other Psikyo's rather easy I would say.

On a similar note, P-47 Aces was cleared by 11 people in one week as well and it's comparatively high up there on that list.

Thanks for your efforts! These lists really help when I can't think of something to play.

Nice list! I wonder how hard Detana Twinbee 2-ALL is compared to Parodius Da 2-ALL?

Regarding to Darius Gaiden, how much the rank if played without autofire?

Also, is the training route in Raiden DX really that easy? I found it's more difficult than Batsugun Special, and why you using 2P ship?

Yes, I managed to get a clear on my first credit ( although it was a crap score). If playing for survival, you get a ton of bombs thrown your way, and the bullet speed isn't fast compared to expert course, or raiden i/ii for that matter. However, if you're trying to go for score, or loop into advanced/expert, then it does become harder mainly due to hoarding bombs/no-miss, and destroying practically every single enemy.

2p ship has faster horizontal movement which made dodging patterns easier imo.

it's not an enormous difference but it is easier than: Gunbird 2, Strikers 1945 1 & 2, Dragon Blaze, maybe Sengoku Blade (?)

This will refer to 2nd loops

Gunbird 2: It might be the hardest Psikyo game to clear, at least it is surely top3. Practice and good patterns is required. Dying is a sin.

Strikers 1945 II: It has the potential to be as hard as Gunbird 2 or even harder, but maybe that would change with sufficient practice? They are comparable. Parts of this loop are absolutely brutal in my opinion

Strikers 1945: Is it as hard as Strikers II and Gunbird 2? Preference. I think the general difficulty is lower, although you may want to play on reaction a little more than usual for Psikyo to clear this. The reason it may be up there is cause you can't carry as many bombs. Also, I assume Boyfriend ship is used. I don't know how good P-51 can cheese.

Dragon Blaze: Another preference kind of game. If you play it "right" and "safe", I think it may be easier than the above. I am too greedy to know ideal survival routes that well...

Strikers 1999: I would be interested in how hard it is with less overpowered ships. Part of its relative easiness to other Strikers can be attributed to X36, I think, although it is also a bit easier designed. It will require practice to beat, but you can be undiligent and use shoddy routes and play a lot on reaction here and still win.

Sengoku Ace: Far easier than all of the above. A matter of some fairly simple memorization and you can beat it without skill.

as for...
Sengoku Blade: how does it place? Below Dragon Blaze? It seems challenging to me, and is clearly on another level from the prequel, but I don't have experience

Gunbird: lack experience with 2nd loop here as well

assuming 1-15 challenging for beginner, 16-30 challenging for intermediate player, 31-45 challenging for veteran, and over 45 as totally nightmare difficulty even for superplayers, I grade them around this:

Gunbird 2: 37-38 (Hei-Cob difficulty seems to be 40+)
Strikers 1945 II: 36-38
Strikers 1945: 35-37 (my experience is slightly insufficient)
Dragon Blaze: 34-35
Strikers 1999 30-32 (how about without X36?)
Sengoku Ace: 17-18
^only cleared 3 of them but I have practiced all the loops before

in the first loop, I think most of them are more even, and I would put them mostly in the 13-15 area, but I think Sengoku Ace and Gunbird (?) are easier and can be 10 or less. Gunbird memories are hazy.

Psikyo games are so survival based and balanced around this, that I don't find it weird to think about them in this way (normally I care about score completely.)

input would be appreciated!

As for psikyo, I've done Strikers 1945 Plus, 1945 II, 1999, and would pretty much agree with the Japanese wiki on where they stand. Haven't played the original 1945 yet but it's probably in the same range as II from what I've seen. Lyv and BOS have both cleared a bunch of psikyo second loops and could help with these ratings too.

1945 II is definitely the hardest of the 3 (that I've cleared), you have very, very little leeway and a death before the blimp stage (2-4 in the default order) and you might as well restart.
1945 Plus & 1999 are about the same difficulty, if you use the Pancake and X-36 respectively. I'd probably rank 1945 plus higher just because you have a 6 bomb limit whereas 1999 has a 9 bomb limit and also gives you more bombs in general.

One think worth noting is that the first loop of 1945 Plus I'd rank MUCH higher first loop of II or 1999, and it's the only one of the 3 games where I used bombs in the first loop out of necessity. I could no-miss/no-bomb II & 1999 without too much trouble after practicing them.

My ratings:
2-ALL Strikers 1945 II (Hayate/Pancake?) - 39
2-ALL Strikers 1945 Plus (Pancake) - 36
2-ALL Strikers 1999 (X-36) - 35
1-ALL Strikers 1945 Plus - 23
1-ALL Strikers 1945 II - 20
1-ALL Strikers 1999 - 19

@chum I agree with Strikers 1945, 35 sounds about right, the early stages are quite difficult but it gets easier towards the end. Also agree with Strikers II, while you have more bombs it's also a considerably more difficult game with lots of tricky situations. Sengoku Ace isn't hard but I'd put it in the early 20s, still just a minor difference.