We saw Clash of the Titans over Easter and we all enjoyed it - good adventure romp with great effects. It's a remake of an earlier movie (1981) and is pretty similar to that story with regard to characters, creatures etc. as well as a few new ones. So maybe that was where God Of War got the inspiration.
Saying that, when you do a film about the Gods, you are limited as to what Gods there are.
Although the Kraken (which was in both versions)is actually a Norse myth.