Horrible. Atrocious. Despicable. Insulting. I'm not sure if words can convey how bad this game is.
Admittedly, I never played the game. I watched my roommate play it. And beat it in a couple hours. Most of that time was spent watching inane cut-scenes for the "special moves." The rest of the time was spent watching him button mash the attack button and easily win the match. Honestly, it's a fighting game for those people who really don't know how to get used to controllers more complex than the NES controller. In fact, I think this game could've easily worked on the NES. Attack, block, and movement. Yep, that's about it.
But really, I doubt anyone expected great gameplay from Celebrity Deathmatch. The gimmicky nature of the game really seemed to scream "rent this first," and at least it was going to be funny. Except it wasn't. At all. I'm not sure a single thing in this game was humorous. Or timely. It was basically a string of 4th-rate, stale pop culture references that American Dad wouldn't even have accepted. The show Celebrity Deathmatch was sometimes funny, and occasionally hilarious. This game induced a multitude of cringes, blank stares, and, towards the end, bleeding from the eyes of those watching the game. I also suspect my aggregate IQ to have dropped a couple of points simply from watching this game be played. I can't imagine what terror it must've wreaked on the brain of my poor roommate.