Super Mario Bros 3. Never beat it until the Allstars version on SNES, but it's the first video game I remember playing. Or maybe it was Gauntlet, but SMB3 was the funner one.
SMB3 was the first game I ever where I won a regional speedrun competition. It was 1992 I think? I blasted Bowser in around 15 minutes on stage, in front of all my friends. I was the coolest kid in school for a couple days.