What is the most disappointing game you've ever played?

Diablo 3

L.A. Noire and Dragon Age Origins

Dragon AGE 2, just too different from the first of the SAGA

Most disappointing.. Well that's a bit difficult because they're necessarily the worst games I've played, or even bad games.

Oblivion and Dragon Age Origins, simply because I bought into the hype surrounding both games up until release and they just weren't what I was hoping for.

Master of Orion 3, I have no idea how they messed up this badly going from MOO2. I really don't.

Dungeons. Too many peopled calling it a Dungeon Keeper-like game pre-release, I should have looked closer.

Fallout 2. One of my favorite games but I was still disappointed by how much silliness was in that game.

Spore. What a moneygrab that one was.

Starcraft 2. I suppose it's mainly because I prefer single-player and the SP in Starcraft 2 was just pathetic when held up against the original. Probably the last Blizzard game I will buy.

Fable 3 anyone?

Postal 3, Gothic 4: Arcania

Duke Nukem Forever: 15 years for this crap...I prefer the older games still to this day.

Mass Effect 3: no ea...just no....

Battlefield 3: Really EA? Take away singleplayer and bots(even on multiplayer) then have to have origin to play it with no steam? I have just about had it with EA.

and last but not least.. Assassins Creed Revelations: Very short story. Wasn't nearly as exciting as Brotherhood,2 or 1. I felt betrayed because I payed so much for it and got so little...took me about 5 hours to beat it from start to finish. Some bugs and felt clunky even when using a controller (did not experience these with the other games) and then.. I ran into ubisofts fun bug... Always on internet or no save games. or if you accidentally lost connection you could not only not save but you couldn't load your saves...they magically disappeared(sounds like something from a commercial)...

Dead Island

Duke Nukem Forever, Might and Magic : Clash of heroes

F.E.A.R. 3

GTA IV

PayDay The Heist....

Blur

Duke nukem forever... don't get me wrong, it could be a good game, but it's the sequel of duke nukem and they took 13 years... i had some expectations about it.

Guild Wars 2.

I love WoW - but GW2? I started with preorder, before the official premiere.
Forced myself to 72, then got bored and then never launched it again.