I'd love to tell you that this movie was great but I'm not into lying.
I very fine cast, a very fine director and a very fine mythological hero lead to a mediocre result. Seems impossible to think at first, right?
In my opinion it IS impossible to fail, unless of course one would be that stupid into changing the "mythological" theme into a "reality" theme. Because that's what they did with this movie.
One would expect to see Gods such as Zeus appearing, and of course mythological monsters such as the Lernaia Ydra. Now you'd object that the Lernaia Ydra WAS in the trailer and I have to inform you that whatever bits you saw in the trailer containing mythological monsters (eg Lernaia Ydra, the Lion of Nemea etc), that was the exact amount you'll see them in the film. It's just in the first 2 minutes' opening and later on you'll realize it is only the story-telling by Hercules's nephew, Iolaos, ergo: not really happening in the film.
The movie portrays Hercules as a mercenary, who is being hired by anyone to provide war services in return for gold. He also has a whole team assembled (/facepalm) in which his nephew (Iolaos) is the PR guy, promoting stories about Hercules being a demi-God, just to advertise him enough to get him hired. There is also a prophet in the team who never predicts anything in an absolute manner, only says things like "the Gods are not telling me...", and even if he does, he is later proved to be wrong.
So is he a demi-God? The movie doesn't say for sure, but everything suggests that he's not. The ending of the movie is not only very annoying and uninformative, but also tries to be educative-moral, saying "anybody can be a hero if he believes in himself" or a similar crap line. (/vomit)
The story evolves around a "job" that Hercules is given, to help a king restore his kingdom's peace blah blah blah. Then there is some sort of mystery regarding how his wife and child died (/facepalm) and in the end there is of course a conspiracy-like turnaround that proves the good guys to be the bad guys blah blah blah (it's boring even to try and make it into words really, you won't even care about the story, trust me).
Let's try to sum up. You will not see Hercules-the mythological figure in this film. If you want to see Hercules go check out the cheap production TV series with Kevin Sorbo. This is just a movie to fit the genre of movies like "Spartacus" or 'Alexander the Great' etc. It is based on the REAL world whereas it should all be MYTHOLOGY (fiction).
On a more technical level, cinematography is OK with some good action sequences. Movie is full of cliché, stupid punchlines, you know, anything that would make the movie "american bullshitty flavored".
So the movie is a joke for the brain, and, if it weren't for the decent direction and the big budget, this movie would be a joke for the eyes and ears too.
Anyway, see it once, it won't bother you that much, but I doubt you 'll ever want to see it again (for any reason).