[Systemz]

Firepower 2000 for SNES. It was 2p simultaneous Gradius-style, but one guy was a jeep and the other a chopper - they both had advantages and disadvantages, but the craziest thing was how incredibly insane the powerups were - instead o fjust collecting the obligatory floating powerup to crank up your machine gun or whatever, you had like 10 different weapons you could cycle through with L and R - shit like flamethrowers and lasers and this wierd boomerang thingy that would hit one thing, fry it, and multiply by 3 to the point where you could fill the screen with these insane boomerangs that would wipe shit out crazy fast. It was harder than beat hell, but it was so much fun since 2p simultaneous games for the SNES were mysteriously few and far between.

Also, while a lot of folks do play it, my vote is for Max Payne as probably the single coolest videogame ever made that didn't blow up into some massive CS insanity - if they had built in multiplayer, that game could have stopped the world from turning.