A good minute and a half to load the game between missions. It makes redoing a failed mission a huge chore because you are sitting there looking at a loading screen for several minutes and the same hassle goes for fast travel.
The driving mechanics are worse than Saints Row, very unrealistic and the cars have a tendency to jerk around unexpectedly.
The shooting ability is okay, but not great.
The best thing I can say about this game is that it has a great idea. This is definitely worth renting if you've been looking for something new, but the innovative idea is executed poorly. So make sure you rent before you buy.