Short but fun
Using the same engine that Halo was created with, adding a touch of humor, 50's style story-line, music that'll make every indie kid cream their pants, and zombies adds up to create a wonderful atmosphere that, while isn't the longest game ever, still creates a great experience.
The humor is weak but entertaining. It relies heavily on bodily humor. Examples include Stubbs' power to fart and complete paralyze his opponents for a little bit, giving him time to munch on brains. The story itself is a breath of fresh-air for the over-used zombie genre of games. Switching roles from zombie hunter to the zombie itself will delight the most hardened of Resident Evil fans. The game is fun. Plain and simple.