When reviewing this movie you should remember it is meant to entertain and this it does very well.
It may not be exactly like the book but nor can it be. A book can offer in one sentence or paragraph what a film often takes 5/10 minutes to convey
Tom Cruise will always give his best which many of us enjoy but some do not. I thought all of the cast were good. It is a typical American action movie which on the whole they make very well and turn them out by the dozen.
You either accept this or not but the object is to entertain and make money for your investors and this film does entertain. It is pure escapism and should be treated as such. Every so often the studios produce a real gem of a movie. I think Source code was one. Avatar another and Oblivion a third to name but 3. There are dozens of others. So this movie is enjoyable but not 5 star by any means.