Why was Immortals so terrible?

I knew it would be bad, so I avoided paying money for it, which is why I haven't seen it until now.

Oddly enough, I'm not going to complain about the costumes.  They were deeply bizarre, but they really went for it, and I respect and admire them for that.  Ares' crest made of swords was rather neat, and certainly effective.

I don't even know what that movie was about.  I mean, Theseus, it was claimed.  But not a Theseus I recognize--and there are many.  Where was Ariadne?  Or Aegeus?  Or the black sail?  And who the hell is King Hyperion?  And what is wrong with his face?  Because it's more than is natively wrong with Mickey Rourke's current face, and that's saying a lot.

And what happened?  Is anyone clear on this?  Who is responsible for what, and why?  And what is the deal with the bow?  Are people more convinced by a temple that no one can navigate than by a labyrinth built for the purpose?  Or by a man with a barbed wire bull head on his shoulders more than an actual minotaur?  In a world where visions are real and there's a magical bow, that actually makes less sense.

What was at stake in the climactic battle?  Do you know?  Does anyone?  Where were the rest of the Olympians?  I feel like they could have helped out.  Why was Zeus hardly old enough to be Athena's most junior uncle?  Why is Kellan Lutz allowed to exist?

Honestly.  You had Henry Cavill, who was sometime aptly cast as a character who, from a certain angle, looks like all the Greek gods at once, and this is the best you can do?