Which are the worst/most disappointing games you've played, and why?

[Parokki]

Hmm... None come to mind immediately, so I'll take a look at my gaming shelf.

Fable - Not a bad game entirely, but the hype made me think it wouldn't be the 100% most rail roaded game I've every played. Don't know why people still listen to Molyneux.. Also wtf is up with my guy doing 3 quests and suddenly being like 50, although my sister remains young and hot? Bah.

Prince of Persia - The acrobatics work very well, but the combat is dull (3 different enemies, 2 different moves you use to kill them EVERY SINGLE TIME), and the plot is damn tedious. You just run from corner of the palace to corner of the palace, and have no idea where you're supposed to go.

Knights of the Old Republic II - Because it was crap. A crap sequel to a great game. -_-

Star Fox Assault - The whole combined arms thing works well and there's a lot of potential, but the game could've used a crapload of more polish. Plot sucks, the enemies are stupid and boring, controls are all over the place at times, and the characters sound and act like they're in pre-school.

Battalion Wars - The gameplay works ok and is kinda fun, but could those guys giving my orders just give them and leave me alone for the rest of the mission? Cartoony warfare where everyone looks goofy and just falls down/disappears when they're killed is still ok, but my superior officer and the enemy commander arguing on the command channel totally my immersion.