the only game related thing I've felt guilt over was spending my hard earned cash on that pos nes game: DinoWarz something something Spondylus /facepalm that troubles me to this day.
...and for never completing the GC game: Beyond Good and Evil. What an absolute gem of a game. I'm a fool for not picking it back up and playing it again even now. Anyone with the ability to give that game a whirl and doesn't is missing out big time.