Good question and it's quite hard to narrow down just one given we had a whole generation that leaped quite dramatically.
Pretty much anything going from SNES to N64 was quite profound. Mario, Zelda, etc...
Other of that era that were huge included Metal Gear Solid over the previous Metal Gear2: Solid Snake.
Grand Theft Auto 3 is another big one.
But Number one.....Kid Icarus: Uprising,
Massimus - "Trump already has democrat support."