80s - Mega Man 2
90s - Starcraft
00s - Warcraft 3
10s - Xenoblade Chronicles

Ohhh ok, that explains it. Well I mean clearly the original release was in the 90s then as you say. That's all that really counts lol

90s - Oddworld abe's oddysee & exoddus
00s - God of War 2
10s - God of War 3

This is an unfair question though, because especially the '90s has multiple games that are better than the other decades' 'Games of the Generation'.

Anyway, while I wasn't alive until the late '80s, I played enough on the 2nd and 3rd Gen consoles owned by family back in the day members to know what's up about the '70s and '80s. I am basing this on the release dates of games here in Europe, which means some early games were '90s games for us, which means that there are games from the '80s I like better than the game I will list here, but aren't there because they are not an '80s game for me.

Here it is;

1970s: #14 Gunfighter, G7000, 1979 (US: Showdown in 2100 A.D., Odyssey2, 1980)
1980s: Duck Hunt, NES, 1987
1990s: The Legend of Zelda: Ocarina of Time, N64, 1998
2000s: Star Wars: Knights of the Old Republic, PC, 2003
2010-2015: Super Mario Galaxy 2 Wii, 2010

Decades I've been alive :

1990s : Pokémon Red/Blue
2000s : Final Fantasy XII
2010s : Xenoblade Chronicles

250000 BC: fire simulator
100000 BC: grand theft mammoth
2500 BC: which naked man can throw a rock furthest
0: Halo
1300: Plague Inc
2001-2013: Hide and Seek
2015: Count the pixels

80s - The Legend of Zelda (NES)
90s - Civilization II (PC)
2000s - Star Wars: Knights of the Old Republic (Xbox)
2010s - Fire Emblem: Awakening (3DS)

90s - Ocarina of Time

00s - Silent Hill 2

10s - The Last of Us/Skyward Sword can't decide :/

80s - Mario Bros.
90s - Pokémon Red & Blue / Ocarina of Time
00s - Modern Warfare / Resident Evil 4
10s - TES V: Skyrim

As far as market influence goes, that's about it, for consoles and handhelds, at least.

00 - guild wars
10 - starcraft 2

didnt played before 2000