Are you f-ing serious? They're making a sequel? Don't get me wrong, I liked the first film even though I realize it's pretty f'd up, but come on! Most likely a rental for me.
No, silly, his adreniline heart that is so amazing it let him survive the 100+ foot helicopter fall, is stolen by Chinese doctors and replaced with an electric one that needs to be recharged to keep him alive while he tries to get his real heart back.
Crank 2 is very much a videogame (heavy on violence and somewhat so on ridiculous sexual situations) put on celluloid, and if you buy into its premise (Chev Chelios has his heart stolen, and has been outfitted with an artificial heart that requires what seems to be any available electrical current to keep it running), then the mayhem through the film should entertain fans of the first installment of the Crank franchise. I admire the high energy level that was virtually maintained through most of the film, even if a lot of it was through cracked-out editing and shooting angles. True, it's got a threadbare plotline (Chev chasing after his heart), but it's all about style and they deliver the insanity in spades.
Don't forget to stay through the credits for a few outtakes.
For sheer filmmaking enthusiasm and anarchy, I give it 2.75 stars, or a grade of B-.