Hm. I had to think about this one, because it is an interesting question. And, it made me think back on EVERY SINGLE game I've every played. So, here was what came to mind:
For the Original Nintendo system
Castlevania III: Dracula's Curse
The Untouchables
For the Nintendo Gameboy
Final Fantasy Legend
Final Fantasy Adventure (I noticed Gameboy had a thing about a game title being 'Adventure'; the first Castlevania game for the Gameboy was titled 'Adventure' as well)
For Super Nintendo
Dungeons and Dragons: Warriors of the Eternal Sun
For Nintendo 64
1080 (Side note; I didn't play alot of N64, and this was the first game I played on it. For some reason, all of the other games for the N64 seemed quite clunky compared to this one)
I couldn't remember any 'flawless' games from the Sega Genesis, so, the Hedgehog loses here.
For the computer
Dungeons and Dragons: Icewind Dale
Vampire the Masqurade: Redemption
Sanitarium
PS1
Darkstone
Diablo
PS2
Wizardry: Tale of the Forsaken Land
Silent Hill 2
Fatal Frame
Mister Mosquito
Dungeons and Dragons: Baldur's Gate