What games did you play through during 2015? The only limitation is that you had to have completed most of it during 2015 (Starting a few days beforehand or finishing a few days after is fine) and that you have to have played through the majority of the game, preferably completed it.
Personally I played
3DS
Monster Hunter 4 Ultimate
The Legend of Zelda Majoras Mask 3D
Xenoblade Chronicles 3D
Shin Megami Tensei Devil Survivor Overclocked
Shin Megami Tensei IV
PS Vita
Persona 4 Golden
Danganronpa 2
Tales of Hearts R
HyperDimension Neptunia Re;Birth 1
Danganronpa Another Episode
Steins;Gate(w/plat)
PS3
Ni No Kuni
Kingdom Hearts 2 Final Mix
PS4
Batman Arkham Knight
Final Fantasy Type 0 HD
Bloodborne(w/plat + DLC)
Destiny The Taken King
Disgaea 5
Tales of Zesteria
Final Fantasy VII
PC
Fate/Stay Night
Tsukihime
Fallout 4
Personally I played
3DS
Monster Hunter 4 Ultimate
The Legend of Zelda Majoras Mask 3D
Xenoblade Chronicles 3D
Shin Megami Tensei Devil Survivor Overclocked
Shin Megami Tensei IV
PS Vita
Persona 4 Golden
Danganronpa 2
Tales of Hearts R
HyperDimension Neptunia Re;Birth 1
Danganronpa Another Episode
Steins;Gate(w/plat)
PS3
Ni No Kuni
Kingdom Hearts 2 Final Mix
PS4
Batman Arkham Knight
Final Fantasy Type 0 HD
Bloodborne(w/plat + DLC)
Destiny The Taken King
Disgaea 5
Tales of Zesteria
Final Fantasy VII
PC
Fate/Stay Night
Tsukihime
Fallout 4