Oh man, you guys don't even know how many old school games I've played.
Guardian Legend (AWESOME game, NES)
Mike Tyson's Punch Out (Duh)
Super Punch Out
Metroid
Super Metroid
Duck Hunt (xD)
SMB 1, 2, + 3
River City Ransum, as stated
Rad Racer (xD)
Chrono Trigger
Radical Dreamers (Emulater + Translation Patch needed)
Final Fantasy III/VI
NES ROM Translation: Chronicles of the Radia War
Street Fighter
Mortal Kombat
Sonic 2 as KTE
Shin Megami Tensei (Rom + Emu + Patch needed)
Final Fantasy III (on the NES, this game is teh pawesums!)
TMNT: Turtles Back in Time (Best. Multiplayer. Game. Ever.)
Zero Wing (Best translation I've ever seen.
Illusion of Gaia/Time
Terranigma
Tales of Phantasia (Rom and patch needed)
Secret of Mana
Seiken Densetsu 3 (Rom and patch)
Star Ocean (It's just a bit too short, IMO, but really, really good. Again, rom and patch needed)
Shining Force II (Rocks)
Bahamut Lagoon (Strategy, need a translated rom...)
Actraiser
Tetris
A boy and his Blob
Joy Mech Fight
Dragon Quest V (Find the patch immediately, this game is awesome! Snes rom)
Man, I can't remember this one game that's super-cool, and it's annoying the hell outta me. >=\
Demon Sword (NES)
Landstalker (Amazingly hard and nostalgic. Great game)
Well, of course Gunstar Heroes
Super Mario World
Yoshi's Island
Ultima VII
Ultima III: Exodus (Hardest. Game. Ever.)
I'm doing horrible right now, I'd usually be listing them off left and right. Meh, maybe I'll give it another go later...