Hmm this is hard.
I'll seperate handheld and home console. I'll also do a PC section. :)
Handheld
Gen 4
Gameboy
Pokemon Yellow (Super Mario Land is a close second)
Gen 5
Gameboy Colour
Pokemon Gold
Gen 6
Gameboy Advance
Yu-Gi-Oh: Worldwide Edition: Stairway To The Destined Duel
Gen 7
Didn't have anything this gen
Gen 8
Ethier Pokemon Y, Samurai Warriors: Chronicles or Fire Emblem: Awakening, not sure at all.
Home Console
Gen 4
Mega Drive
Sonic The Hedgehog (Moonwalker as a close second)
Gen 5
Playstation 1
Gundam Wing: Battle Assault 2
Gen 6
Gamecube
Super Smash Bros. Melee
Gen 7
Wii
Wii Sports (Mortal Kombat : Armageddon is a close second)
Gen 8
Wii U
Super Mario 3D World
Hybrid
Gen 9
Switch
The Legend Of Zelda: Breath of the Wild
PC
Windows 95/98
Age of Empires
Windows XP
Star Wars Empire At War/Forces of Corruption
Windows 7
Total War: Shogun 2 or Skyrim, not sure.
Windows 10
Total Warhammer 2