80s & early 90s:
Rocky's Boots (basic wiring + gadgets)
Robot Odyssey (advanced wiring + city to explore)
Alley Cat (minigame collection)
Digger (you can get Digger HD on PSN, but I'm referring to the original)
Jetpack (early physics-based platformer)
Paganitzu (top-down puzzle-exploration)
ZZT (the Little Big Planet of it's day)
Robomaze 2 (difficult but fun platformer)
Hexxagon (fun board game with amusing animations)
Captain Comic (platformer / adventure game, would be called a Metroidvania nowadays)
Hugo's House of Horror (classic adventure game)
Ken's Labyrinth (early FPS/adventure game by Ken Silverman, the guy who went on to make the engine for Duke Nukem 3D)
VGA Miner (similar to a 2D Minecraft but a million times harder and more random)
Stunt Island (vehicle simulation + video recording and editing + vehicular missions = unique game)
Quarantine (Doom + Crazy Taxi)
Super Solvers Ancient Empires (a hardcore platform-puzzler disguised as "educational")