The plot isn't really that simple. The FBI do the initial exposition, with all of the history, mysteries, politics and enemies list. That makes the plot more fun to follow. But it's really just about people getting shot and stuff getting blown up, and vice versa.
The bad guys gunning for Piven include - wait, I'll do it list style
- A pair of black lesbian killer cuties, played by Alicia Keyes and Taraji Henson
- Three 80's-style punk meth-head redneck berserkers, lead by Chris Pine (Capt. Kirk)
- At least 2 masters of disguise - I'm not sure how many because they were in disguise
- A team of bounty hunters who want Piven for jumping bail, lead by Ben Affleck in an awesome Fu-Manchu moustache
- Piven's bodyguard, played by conscious rapper Common
This is squarely in the hip ultra-violent style of Guy Ritchie or the Crank movies. But I've got to say, it isn't quite up to their standards - not quite as tricky, fresh or imaginative. But I bet everyone had a good time hanging around Tahoe (I think we've stayed at some of the hotels shown), and we had a good time watching them.