I'll keep this review short, as the description covers most things, with a rather biased slant, of course.
However in this film, it lives up to expectations, with plenty of storyline, as with most crime-related films, a nice plot twist or 2 near the end (which I obviously wont spoil), and plenty of guns, corrupt cops, gangsters, all the cool things you'd expect to be in a movie.
It does get slightly random a couple of times, however to be honest, it remains mostly believable and always gripping.
All in all a great film, I personally loved it, it kept me glued to the screen all the way through, but it may not be to everyones taste. If you unsure, rent it first, but to be honest, its a good enough film to just buy.