The Nintendo years:
1990: Super Mario World
1991: A Link to the Past
1992: Ultima Underworld: The Stygian Abyss
1993: Mega Man X
1994: Super Metroid
1995: Donkey Kong Country 2: Diddy's Kong Quest
1996: Super Mario 64
The PC years:
1997: Fallout
1998: Ocarina of Time
1999: System Shock 2
2000: Deus Ex
The GameCube vs PS2 years:
2001: Ico
2002: Metroid Prime
2003: Ratchet & Clank: Going Commando
2004: Half-Life 2
2005: Resident Evil 4
2006: Kingdom Hearts 2
The PC revival:
2007: The Witcher
The Playstation years:
2008: Grand Theft Auto IV
2009: Demon's Souls
2010: Fallout New Vegas
2011: Portal 2
2012: The Walking Dead
2013: The Last of Us
2014: Alien Isolation
2015: The Witcher III
2016: Dishonored 2
2017: Breath of the Wild
2018: God of War
