NES - Super Mario Bros 3
Mega Drive - Sonic The Hedgehog 2 or Golden Axe
GBC - Pokemon Red
GBA - Pokemon Ruby
PS1 - Final Fantasy VIII
PC (90's) - Dungeon Keeper
PS2 - Final Fantasy X
PC (00's) - RollerCoaster Tycoon 2
PS3 - Call of Duty: World at War or Tekken Tag Tournament 2
PS4 - Rocket League

This is tough. It's hard not to fit in some favourites like Kingdom Hearts, Warzone 2100, Tekken 7, or Micro Machines for the SNES. Some I couldn't choose between.