first two-player shmup

[DazTM]

Hi everyone, I'm putting together an article about innovative shooters and I could really do with some help. I'm trying to source what was the first shmup to feature simultaneous two-player and smart bombs. The earliest I can think of is Salamander and tiger Heli, but I have a feeling these are wrong.

[Mortificator]

The smart bomb is from Defender.

Space Invaders II and the 2600 port of the original game allowed two simultaneous players, and the shooter ancestor Spacewar was 2-player-only. I don't think 2-player can be considered an innovation when it's been around since the genre's pre-history.

[DazTM]

Space War was against another player though. I was looking more at both of you working together. Good call on defender though, I've been playing that all afternoon as well

[BrianC]

The 2600 port of SI had a co-op mode. I'm not sure if it's one of the earliest co-op shmups, but Atari's 1982 Space Duel (not to be confused with the already mentioned Space War) arcade game had 2 player co-op.