Various games I've enjoyed: (some classics, some more obscure)
Turrican (1-3, though 2 is the best). Platformer, metroid style
Alien Breed (pretty much all of them. Start with the 92 special edition)
Alien Breed 3D (FPS)
Gloom (FPS)
Superfrog (platformer)
Battle Isle / Historyline (turn based strategy)
UFO enemy unknown (pretty much the best strategy game ever)
Civilization AGA (strategy)
Hired Guns (action RPG first person thingie, amazing once you figure it out)
Super cars 2 (racing game, two player)
Jaguar XJ220, Lotus 2 (more racing games)
Sensible world of soccer (soccer
)
Speedball 2 (violent sports game)
Warlords (turn based fantasy wargame)
Banshee (AGA, pretty much the best shoot em up ever IMO)
Lemmings 2 (puzzle game)
Beneath a steel sky (adventure game)
Eye of the beholder 1-2 (D&D rpg)
Heimdall 2 (isometric rpg)
Theres a few to get you started
These are all games that run on my 1200 without relokick or anything else (though Jaguar you gotta get a cracked version for this). A few of them have HD install options but there's always WHDload I guess