Let's make a list of shmup gameplay innovations & firsts.

[Drum]

What it is, when it first appeared and what game it first appeared in.

I will maybe make this alphabetical when I can be bothered.

I am going to include borderline games in this because back in the day what wasn't a borderline?

Smart bomb: Starship 1 (1977, Atari). You have a limited stock of these and they destroy all enemies on-screen.

Rank: Star Fire (1978, Exidy). As you shoot enemies, they get harder to kill and award more points. When you get hit, rank drops back to zero.

Chaining: Exerion (1983, Jaleco). I don't 100% know how it works in this game. I know you get more and more points for shooting a bunch of guys in a row. Is it just time between hits that kills your combo, or do misses count? Need more data.

Power up: This one is kind of tricky. Moon Cresta (1980, Nichibutsu) is kind of a contender - you get extra power when you die. Galaga (1980, Namco) is another possible. The earliest one I know of that comes closest to what was most-emulated is probably Space Fury (1981, Sega).

Point-blanking, or points based on proximity: Sheriff (1979, Nintendo). You get more points if you kill the bandits after they've entered your little fortress. I, Robot (1983, Atari) further developed this by adding more variables - basically, the closer you are when you shoot them, the more points you get. I think there may be another early example but I can't remember!

Shield: Tunnel Hunt (1979, Atari). Pressing the shield button makes you invincible for as long a hold it down. You have a limited amount of shield energy that is drained when you use it. Further built on in Phoenix (1980, Amstar).

Charge shot: Space Beam (1980, Irem). The longer you go without shooting, the longer and thus more effective your laser is. Irem would further develop this idea in R-Type (1986).

Polarity: Before Dimahoo (2000, Raizing) and Ikaruga (2001, Treasure) there was Mighty Monkey (1982, Universal). You have two forms - monkey riding a cloud and dragon head. Only the monkey can shoot. Some enemies can only be shot by the monkey form, others can only be destroyed when you run into them with the dragon head. Any enemy shots are lethal to either form. This is a debateable case, I guess.

Enemy splitting: I can't find which of these was first, so I'm gonna give it to Asteroids (1979, Atari) though it was released late in the year. Destroy asteroids and they split up into itty bitty baby asteroids. In Space Fever High-Splitter (1979, Nintendo) enemies split up unless you shoot them dead-centre.

Co-op: Wizard of Wor (1980, Midway). Two player maze shooter where you can pretend you didn't really mean to shoot the other player. Also see Space Duel (1982, Atari), which introduced a tethered co-op mode. There are a bunch of other shooters where you can join up with a friend into one form but I am too lazy to list them.

Bullet grazing: Krull (1983, Gottlieb). Run in front of the boulders on the first stage and you get points! The game is basically a shooter, but you don't actually shoot in that stage, so we'll have to give it to Raiden Fighters (1996, Seibu Kaihatsu).

Slow Motion: Astro Blaster (1981, Gremlin/Sega). Press a button and everything slows down, making enemies easier to waste - but fuel drains just the same so you gotta be careful. Get an extra warp every wave or life.

Fast Motion: Mag Max (1985, Nichibutsu). Press a button to make everything go crazy fast for no reason in particular. I couldn't get this to work in MAME so I'm just gonna take the internet's word for it.

Rewind: Chouji Meikyuu Legion (1987, Nichibutsu). Press a button to make enemies and enemy bullets reverse their paths to a short amount of time. You only get a few of these.

Secret bonus: Astro Blaster (1981, Gremlin/Sega). There are something like 30 different hidden score bonuses to discover. No-missing a stage etc. gets you a secret message and some points. Xevious (1982, Namco) had hidden spots to bomb for more points.

Bullets turn into point pickups: DoDonPachi (1997, Cave) is the first one I can find. Whenever you kill a boss or sub-boss any bullets they have on-screen turn into golden sparklies for you to pick up.

I will add more when I think of some, feel free to make corrections or add new ones!

[ChainsawGuitarSP]

Star Fire came out the year after Space Invaders, which invented rank in the form of enemies speeding up as you decreased their numbers.

[Drum]

Star Fire came out the year after Space Invaders, which invented rank in the form of enemies speeding up as you decreased their numbers.

Actually the same year (Star Fire was first released in Dec '78), but Space Invaders was definitely first. I kind of want to say that Space Invaders is a stretch, but off the top of my head I can't put up serious opposition. My general feeling is that 'gets faster as you shoot more guys' is maybe a kind of proto-rank, but it kind of needs a little extra something. Like, there isn't anything you can do to slow down the aliens in Space Invaders except complete the wave - it adjusts with each kill but not each failure.

[DocHauser]

Good list. I'm pretty sure I've got Mag Max to work in my version of MAME, so I might try it later. I don't actually remember the 'fast motion' option, although I haven't played it that much.

[Sumez]

Also rank shouldn't be a natural increase in difficulty through ordinary progression (such as shooting the aliens, which is the only thing you CAN do in that game), but an adjustment that makes the game more challenging to players who do well, while players who aren't as good might be able to get just as far with a much lower increase in difficulty.

[Drum]

Also rank shouldn't be a natural increase in difficulty through ordinary progression (such as shooting the aliens, which is the only thing you CAN do in that game), but an adjustment that makes the game more challenging to players who do well, while players who aren't as good might be able to get just as far with a much lower increase in difficulty.

In addition to shooting guys, you can get shot in Star Fire, which drops the enemy difficulty/point value to the lowest. Or you can fail to shoot the enemies fast enough and they fly away without harming you (which isn't possible in Space Invaders), which neither increases nor decreases difficulty. You do earn an extend for getting enough points. I grant that it is a borderline case in a borderline case, but it approaches rankosity.

[ChainsawGuitarSP]

There are still shmups that follow the 'never drops' rank, so I don't see why there's only one perception of it. Most Darius games are impossible to recover from death after all. Speaking of which, were there any games before that that had a branching paths/stage select feature?

[Drum]

There are still shmups that follow the 'never drops' rank, so I don't see why there's only one perception of it. Most Darius games are impossible to recover from death after all. Speaking of which, were there any games before that that had a branching paths/stage select feature?

Berzerk has branching selectable paths if that counts.

I'm still not convinced on Space Invaders re: Rank (this coming from the guy pushing Star Fire, I know). It's not something you can control in Space Invaders, unlike in Darius. You see the 'max rank' in the basic course of a level or you die. I do think the tension-building it introduced at least warrants a mention - probably even its own seperate entry - as a ton of games of its kind use that as a core feature.

[Naglfar]

Speaking of extends, where did those originate? Were they in Space Invaders?

[mesh control]

What was the first game to allow players to exploit enemy bullets as offensive tools?

Like Giga Wing or the Psyvariar series (to an extent).

[BeruBeru]

Touhuo - So many bullets!

[RNGmaster]

Touhuo - So many bullets!

gb2/lunatic red

Seriously, stop pimping Touhou whenever you can. Dodonpachi's final attack has the same bullet count at most Touhou attacks, and that's in 1996.

Anyway, the dawn of bullet hell has been discussed so many times it's not even fair to talk about it here.
garegga did it first

[Naglfar]

Touhuo - So many bullets!

gb2/lunatic red

Seriously, stop pimping Touhou whenever you can. Dodonpachi's final attack has the same bullet count at most Touhou attacks, and that's in 1996.

Anyway, the dawn of bullet hell has been discussed so many times it's not even fair to talk about it here.
garegga did it first

You aren't the best at spotting a joke, are you?

[RNGmaster]

You aren't the best at spotting a joke, are you?

I can detect stupidity at a further distance than I can detect humor.

[Bananamatic]

Cho Aniki - Making the player question his sexual orientation

[Treasurance]

Touhou has the honor of inventing major faggotry

[BeruBeru]

You aren't the best at spotting a joke, are you?

I can detect stupidity at a further distance than I can detect humor.

In this case it was a joke, and to be honest, DDP is my favorite shmup up to date

[IseeThings]

What about playing different versions of the same level but with different difficulty levels, like Border Down?

The remake of Fantasy Zone 2 does this rather explicitly too, with Light and Dark versions of each level, the original Fantasy Zone 2 had it as a looser concept.

Actually the whole 'destroy all bases to proceed to boss' mechanic is there too.

Ability to change ship movement speed? Games in which it had a real effect on things around you rather than just making the ship move faster (Skull Fang?)

Upgrades which can be purchased..

Actual ability to customize ship with upgrades (I'm thinking X-Out on the Amiga where you essentially build your ship)

Different routes through the game (Darius?)

Special Moves (I'm sure there was a shooter with SF style quarter circle specials, double tap dash moves etc., but I can't remember which)

Player movement momentum (Tecmo's Backfire is irritating in this sense)

Mixed orientations.. Terra Cresta? Thunder Blade (kinda, it has '3D' and vertical)

Critical points on bosses (Striker 1945 III and probably many earlier ones)

Detachable ship parts (Xexex, Ironclad..)

Players joining together? Blasteroids, Dogyuun?

Some of these aren't really shooter specific things however, and there are probably earlier examples of many.

[Uzumakijl]

Players joining together? Blasteroids, Dogyuun?

Twinbee?

[dunpeal2064]

Touhuo - So many bullets!

gb2/lunatic red

Seriously, stop pimping Touhou whenever you can. Dodonpachi's final attack has the same bullet count at most Touhou attacks, and that's in 1996.

Anyway, the dawn of bullet hell has been discussed so many times it's not even fair to talk about it here.
garegga did it first

I would go with Batsugun over garegga, or even V-V.

As for curtains of slightly slower patterns, I would credit ddp more than garegga. Just my 2 cents

[ZOM]

Players joining together? Blasteroids, Dogyuun?

Twinbee?

Side Arms Hyper Dyne.

[IseeThings]

then of course you have games with fairly unique concepts.. (if you consider them shmups could be debated)

Segas SDI with the joystick for movement, and trackball to aim your fire (it still plays like a shmup tho)
Change Air Blade, which is more of a VS shooter but in modern style
Konami's Scooter Shooter which combines a shooter with a 2 player 'race' style game.
Choplifter with it's 'rescue the hostages' theme (or Defender although you could just kill them all there ) (although Jaleco's Desert War copies that concept rather closely, as did Apocalypse on the Amiga)

these aren't just concepts you could drop into any game like some of them which have been mentioned, more ones the games were designed around.

I think Twin Eagle 2 might have been the one with SF style moves come to think of it.. which brings another interesting idea, fully destructible backgrounds. Things like Xevious had ground targets.. Raiden let you destroy some of the more generic scenery, but Twin Eagle 2 let you destroy near enough everything you could see in the background.

[Wenchang]

Was Wizard of Wor before Rip Off?

[Despatche]

I think Tac/Scan needs to be mentioned for something. Probably something related to Terra Cresta or even Galaga.

Dodonpachi...that's in 1996.

Released in the earlier half of '97; I've heard February.

Actually the whole 'destroy all bases to proceed to boss' mechanic is there too.

You may be forgetting Thunder Force (1983).

Special Moves (I'm sure there was a shooter with SF style quarter circle specials, double tap dash moves etc., but I can't remember which)

Probably not what you're thinking of, but there's Batsugun.

Critical points on bosses (Striker 1945 III and probably many earlier ones)

Define this, exactly. The issue is that you could name a lot of older games where all "large enemies" have one attack point anywhere (Eliminator, et al.).

Detachable ship parts (Xexex, Ironclad..)

Terra Cresta was definitely doing this first, unless there's some earlier Western game I'm missing. Later, there was R-Type, which inspired the likes of Xexex.

Change Air Blade, which is more of a VS shooter but in modern style

They're not particularly similar, but Twinkle Star Sprites (even the Touhou clones of it)--and probably some older '80s games I can't think of--did the "versus shooter" thing long before CAB.

Was Wizard of Wor before Rip Off?

wp specifically points out that Rip Off was "the first co-operative shmup", so I'd guess not.

[IseeThings]

Critical points on bosses (Striker 1945 III and probably many earlier ones)

Define this, exactly. The issue is that you could name a lot of older games where all "large enemies" have one attack point anywhere (Eliminator, et al.).

The whole 'boss reveals weak point, can be killed with one precise hit' mechanic it has. It doesn't seem like the biggest innovation in the world, but I can't actually think of anything else that does it before that.

Many of the things I've mentioned I may have got the examples wrong, they were mentioned as points to possibly stimulate the conversation.

Twinkle Star Sprites is closer to Scooter Shooter in that it's a split-screen game. Both combine elements more traditionally found in other genres.

How about Short-range melee type attacks?

[Muchi Muchi Spork]

The whole 'boss reveals weak point, can be killed with one precise hit' mechanic it has. It doesn't seem like the biggest innovation in the world, but I can't actually think of anything else that does it before that.

The Death Star...

[IseeThings]

The whole 'boss reveals weak point, can be killed with one precise hit' mechanic it has. It doesn't seem like the biggest innovation in the world, but I can't actually think of anything else that does it before that.

The Death Star...

Can that actually be destroyed *without* hitting the critical point tho?

The concept hinges on providing alternative ways to destroy the bosses, not a single way (many games have bosses which are vulnerable in only one spot, less seem to provide strategic opportunities to kill the boss based on a weak point)

Here's another one.. bit of a novelty feature, destroyable HUD gfx. Thunder Dragon 2 does this, you even get a bonus for it :-p

Timed bosses? When was that introduced? Some games even have visible timers, the majority don't. Some the boss will remain there until you actually kill it.

[stryc9]

How about selectable weaponry, or multi-directional firepower?
Or adjustable ship speed?

[BPzeBanshee]

How about selectable weaponry, or multi-directional firepower?
Or adjustable ship speed?

Thunder Force III was in 1990 which had adjustable ship speeds, and the original Thunder Force (1983) as mentioned by Despatche consisted of multi-directional gameplay, and therefore firepower I suppose.

There's probably earlier titles than those though, I think.

[Obiwanshinobi]

Bosconian (1981, Namco) had sort of chaining - to quote Wikipedia:

Enemies occasionally launch formation attacks — destroying the leader causes all remaining enemies to disperse, but destroying all enemies in a formation scores extra bonus points.

Which shooter had pioneered the multipart body of your ship with no "main" part? I.e. each part is destructible and you fight to the last part, no matter which one it is. Surely NOT Cannon Fodder, but maybe Mercenary Force/Tenjin Kaisen (1990, Meldac/Live Planning/Lenar)? Or was the 8-bit Final Zone like that before?

What was the first game to allow players to exploit enemy bullets as offensive tools?

Like Giga Wing or the Psyvariar series (to an extent).

In R-Type Delta (1998, Irem) you charge Delta Attack (bomb) by absorbing bullets (and destroying stuff) with the Force.

Ability to change ship movement speed? Games in which it had a real effect on things around you rather than just making the ship move faster (Skull Fang?)

Battle Formula (1991, Sunsoft)?

Where did a yo-yo/boomerang type attack appeared first? Zanac (1986, Compile)?