A "shoot em up" type game, except unlike the movie Shoot em Up, this one is actually good.
As a Gears of War shooter, it's bloody, well paced, and has enough complexities to the story to keep it from being a cut n paste plot. I would go as far as to say it's a better Gears of War because there are about 50 more ways to kill someone in Bulletstorm.
As a Duke Nukem comedy, it actually made me laugh at a few parts (which is rare in a video game that isn't made by Sierra or LucasArts). The "whatever you do, just do it quiet" response was fantastic.
And if you think the voice of the main character sounds familiar, it's because it's Steve Blum, the voice of DoW's Cyrus, Wolverine in the X-Men cartoons, Starscream in Transformers, Black Ops, Guild Wars 2, New Vegas, Oghren in Dragon Age, Mass Effect 2, Killer Croc in Arkham Asylum.... etc etc etc. Seriously this guy is THE voice of everything. IMDB him.
The whip, weapons, and different ways to kill people kind of get old, and the levels are basically just different sets for you to fight multitudes of baddies, but you really don't mind too much since you'll spend the entire game trying to get all the kill accomplishments.
The game is also a little on the easy side. You can bum rush the enemy on normal mode and not worry about dying. The "take cover" near death warning can be ignored and you will still survive. And if you do die, usually because you didn't follow instructions against a boss, the checkpoints are so frequent that you rarely lose more than a minute or two of progress.
All in all, this game is highly entertaining, beautifully designed, filled with epic scaled bosses. I played it all the way through in one sitting (about 7 hours worth), so you may just want to rent it and finish it, then decide if you still want to own it.