I have a problem. Well, to be completely fair, most of these came in bundles of some sort or another, but still. I have a problem. HLTB says I'm up to 3.5 months, btw.
Spoiler!Left out a few games with no definitive end game (i.e. RTS)
10 Second Ninja
99 Spirits
Always Sometimes MonstersAssassin's Creed*
ArcaniA
ArcaniA: Fall of Starrif
Assassin's Creed*
Assassin's Creed II
Assassin's Creed III
Assassin's Creed IV/Freedom Cry
Assassin's Creed Brotherhood
Assassin's Creed Revelations
Aveyond: Lord of Twilight
The Banner Saga
Batman: Arkham Asylum
Batman: Arkham City
Batman: Arkham Origins
The Binding of Isaac
Bioshock
Bioshock 2
Bioshock Infinite
Bone: Out from Boneville*
Bone: The Great Cow Race*
Bravely Default**
Breath of Death 7
Brothers - A Tale of Two Sons*
Child of Light
Crimzon Clover
Cthulhu Saves the World
Cubic Ninja
Dark Souls
Death Ray Manta
Detective Case and Clown Bot
Deus Ex
Deus Ex: Human Revolution
Deus Ex: Invisible War
Deus Ex: The Fall
The Elder Scrolls III: Morrowind
The Elder Scrolls IV: Oblivion
Fable Anniversary
Fairy Fencer F
Fallout 3
Fallout: New Vegas
Final Fantasy 7*
Final Fantasy 8
Final Fantasy 13
Forward to the Sky
Get Off My Lawn
Goats on a Bridge
Gone Home
Gothic
Gothic 2
Gothic 3
Greyfox
Gunman Clive
Hack 'n' Slash
Half Life*
Half Life: Opposing Force
Half Life: Blue Shift
Half Life 2
Half Life 2: Episode One
Half Life 2: Episode 2
Half Life 2: Lost Coast
Labyrinthine Dreams
Last Word
Last Dream
Left 4 Dead
Left 4 Dead 2
LEGO Hobbit
LEGO Lord of the Rings*
LEGO Harry Potter
LEGO Harry Potter (5-7)
LEGO Batman
LEGO Batman 2
LEGO Batman 3: Beyond Gotham
The Legend of Heroes: Trails in the Sky
The Legend of Zelda
The Legend of Zelda: Oracle of Ages*
The Legend of Zelda: Oracle of Seasons*
The Legend of Zelda: Twilight Princess*
Life is Strange
LYNE
Mario Kart 64 (complete all cups)
Mario Kart DS*
Mario Kart: Super Circuit
Mount & Blade: Warband*
Millennium - A New Hope
Okamiden
One Piece: Unlimited World Red
One Way Heroics
Paper Mario (N64)
Paper Mario: Sticker Star*
Pixel Piracy
Pokémon Trozei
Pokémon Mystery Dungeon: Explorers of Sky
Portal 2*
Remnants of Isolation
Savant: Ascent
The Secret World
Shantae
Spec Ops: The Line
Spoiler Alert
The Stanley Parable
Stealth Bast*rd Deluxe (the * is not in the actual title)
Superbrothers: Sword and Sworcery
Super Mario Bros.
Super Mario Bros. 2
Super Mario Bros. 3
New Super Mario Bros. (DS)
Super Mario 64 DS
New Super Mario Bros. 2*
Super Mario 3D World
Super Mario Land
Super Mario Land 2
Tales of the Abyss*
Tales of Symphonia (next year)
Tales of Zesteria (October 20)
This War of Mine*
Tomb Raider*
Tomb Raider I/Anniversary
Tomb Raider II
Tomb Raider III
Tomb Raider: Last Revelation
Tomb Raider: Chronicles
Tomb Raider: Legend
Tomb Raider: Underworld
Lara Croft and the Guardian of Light
Trine
Trine 2
Tsukmogami
Valkyria Chronicles
Whisper of a Rose
The Witcher
The Witcher 2
Xenoblade Chronicles
* partially completed (an hour+)
For what it's worth, these are the games I've finished since my last backlog post (March 11):
Spoiler!Age of Empires 2, depending on how you define "beat" a game with no end goal
Dev Guy
Epic Battle Fantasy 4
Greyfox
Nekopara Vol. 1
One Piece: Romance Dawn
To the Moon
Toren