Soul Eating Games

Spiral Knights

fallout, assassins' creed...

Dark souls, Demons Souls, The Last of Us, Metro 2033 is pretty good too

King's Bounty series

Dark Souls. It will eat your humanity away. You though it have only been a few hours, you opened your window and then you realized that 70 years has passed. Seriously though, this game is cruel yet highly addicting. whenever you rage quitted that game is sitting on your library, shoving it's ass to your face while taunting you. Challenging you to walk through hell once more. Which of course we'll accept it since we are badass n bossy as hell.

Fallout 3 and New Vegas. Welcome to the end of your (social) life.

Metal gear solid saga / Dark Souls / Monster hunter / Deus Ex saga / and i should reccomand you Psychonauts

Warframe.

WTF people, Skyrim, period.

The binding of Isaac, Beat Hazard, also The walking dead is cool but you can beat it in a day. Otherwise play a UEFA in PES2013 with 30-minutes-long matches and Super star level, with the worst team possible, play until you win the cup.

Soul eating? Minecraft easily. I played that game for a stupid amount of time.

But something off the wall, Team Fortress Classic -- so much more fun than Team Fortress 2. It's a really different game that is a lot more fast paced and requires a lot of skill.

If you're a completionist, the Ys games sure can do that. Between Ys Origin and Ys: The Oath of Felghana, I have 1000+ hours of gameplay and still not 100% complete in those games. Nightmare difficulty in those games sure can give Dark Souls a run for its money, especially in time attack.

XCOM and Civ 5

Fortix, dur.

But seriously - Civilization V (or any of the Civs really), and maybe planetside 2, if you like that kind of stuff

Try to become a breeder in Pokemon. breeding for good IVs without using any manipulations is can definitely consume your soul.

Try Giana Sisters: Twisted Dreams.

Borderlands and Borderlands 2.

Dishonored and the new Tomb Raider kept me playing right to the end and for me that's rare these days.

The whole mass effect series kept me locked in a cupboard for about 1 month and a half now.

Mount and Blade.

Far Cry 3

It has maybe a 12 hour story line, but I somehow have put over a hundred hours in the game. And I never even touched multiplayer. The game world is so enveloping I can spend countless hours just running around the jungle hunting animals and collecting crap.

Any Civilization game. "One more turn!" will become your mantra. Even after you've made peace with every other nation, and then went back on your promise and blitzed them with tanks, and then nuked all their capitols and the game says 'You've won!', you'll still keep wanting to press the 'next turn' button.

Oh, and HEROES III!

Team Fortress 2 (with hats)