I found that the pacing and action moved the movie along much better than the first, though the main character, a cop named Eric Matthews (Donnie Wahlberg) is extremely irritating. He only does two things in the movie-he yells and he cries. In fact, his character remains exactly the same from beginning to end, which I suppose was the point, but it is difficult to endure. He's your ultimate unhappy/corrupt cop stereotype.
There's a new batch of people abducted by the serial killer Jigsaw (Tobin Bell) and they all have something in common with each other. Matthew's teenaged son is also among them. They find themselves in a boarded up, booby-trapped house and are told that they've been exposed to some form of nerve gas. If they don't solve the puzzle and find the antidote in two hours they will die, if they aren't killed off by some other means first.
Amanda (Shawnee Smith of THE BLOB), the only survivor from a previous Jigsaw abduction, returns and finds herself among this group. Emmanuelle Vaugier of HOUSE OF THE DEAD II, CERBERUS, PAINKILLER JANE is type-cast again as a bad girl/prostitute.
Although the "surprise" at the end was not totally unexpected it nevertheless worked and sets up the possibility of many future sequels. Overall, I enjoyed part 2 more than 1.