The funniest game ever, or at least right up there with Portal.
The game also has a plethora of amazing levels, snow levels, fun as hell turret levels, though beyond all of them are the expansive village levels you can blow the hell out of.
But above all, the game is seriously funny, almost every cutscene is a classic, with enough star wars references, sly monty-pythonesque humor, and anti human robots to make anyone love it.