After watching that...I take back all comments I said about one copying the other. I realize now that both are actually copying Greek Mythology lol.
Nowadays, any respectable Video game designer or Movie director...doesn't just slap a few creatures into a Game/movie and say its based off of Greek Mythology. They research, study, and get detailed description about the Creatures, Critters, and Monsters of Greek mythology and make them as realistic or graphic as possible. And since both are pretty much studying the same culture, the creatures and ideologies are gonna come out simular.
I agree to the whole Entertaining thrill both are trying to grasp. Guess the idea of being a warrior fighting monsters in olden days is still an appealing form of entertainment. This movie is that and if nothing else at least visually appealing.