Terrible acting, screenplay and direction.

It's funny, it's tense, it features two great performances from two actors and the director expertly creates a web of odd tension where you actually don't know what is happening for the majority of the run time.

The thing I enjoyed most about the film is the fact that it doesn't shy away from being a super-sized-cliche;

Yes, absolutely, there is fun to be had, as well as many, many things to go boom, all amid an atmospheric urban jungle.