I've played in something like chronological order. * means it's a game I wrote.
Star Frontiers (actually this was my first RPG)
I don't know if this counts, it's kinda sorta Sci-Fi Marvel Super Heros (second RPG)
*Galactic Legions (First game I wrote, space opera type game, currently re-working)
Robotech
TMNT
Cyberpunk
Shadowrun
Star Wars
Star Trek
Space 1889
Champions
Rifts
*The Artifact (Second game I wrote and my current project)
*Aftermath (third game I wrote, post apocalyptic world)
Gamma World
Alternity
*Space Dust (open source miniature space battles, current project)
Hmmm. I'm missing some but that's a pretty good start. Sorry I haven't played the games you guy's have wrote. It's usually all I can do to get enough time to write or playtest ideas. I've always wanted to play Traveller but never had the time or circumstances.