Generally speaking, they're never really that good: in fact, I'm struggling to think of any that are even half-way decent.
Unfortunately, Hitman isn't.
As I only really have a passing acquaintance with the source material, I can't really say how closely this sticks to it, but what I can say is: boy oh boy, is this violent. I've just noticed that Flixster is showing it as a '12' rating: if that's true, it must either be (a) some sort of edited version or (b) one of the most inapt classifications I have seen: blood, guts and gore, strong language and full-frontal nudity do not, in my book, equal a 12!
This has a pre Die-Hard Timothy Olyphant as the Hitman of the title, a man with no name who is simply known as 'Agent 47'. As is the way of things in movies, he gets drawn into a conspiracy when he is set-up after carrying out a job, leading to a climactic showdown in the final reels.
I'd heard there's a new Hitman movie out later this year (2015): it will be interesting to see how (or even if) that newer films pertains to this - will it ignore it? Works these events in? Only time will tell ...