The original Mario 64 was so choice, and that Zelda game that came after that was classic. Haven't played any games in years but remember those fondly from the cartridge days.
Oh, and Wonder Boy in Monster Land 3 ... pure gold.
Tetris! I am so good at that game it's insane. End of Story. Best ever.
The original NES version only though. Although, I am also pretty amazing at the Facebook version tbh. The rest of the versions I have tried suck.
(NES) Dusty Diamonds All-Star Softball (I still play it some to this day - so bad it's good) Yes, I still have an original NES that works.
Call of Duty (PS3)
NHL '94 (Sega) - Greatest sports game ever made. Hands down. Tecmo Super Bowl comes close though.