Aside from the humans, about half the costumes, and some furniture, what was NOT computer generated in this movie? Not much. And given that a number of the characters on screen are "gods" (who are about 80cm taller than your average human), even some of the people are sometimes CG. All this CG is somewhat distracting. And even though the CG is often pretty obvious, it's generally fairly pretty. But much more distracting than that is a bad script coupled with some amazingly hammy acting, some of it from otherwise good actors.
The premise sees us in Egypt several thousand years ago, a country ruled by gods. Bek (Brenton Thwaites), a human thief, doesn't care much about the gods: all he cares about is making a good life for himself and his true love, Zaya (Courtney Eaton). But Horus, son of Osiris, is about to be crowned king of Egypt - this is a really big deal that Zaya cares about, even if Bek doesn't. So they attend the coronation - where Osiris's brother Set (Gerard Butler) puts in an appearance, killing Osiris, blinding Horus, and crowning himself. He's not a very good king, and Bek is convinced to aid (exiled, blind, and sulky) Horus.
Thwaites has a certain amount of charm as Bek, although he's not doing a great job. And the big names aren't exactly leading by example: Rush's "I'm the god of the sun and I'm an idiot" performance is probably the worst (particularly given that he's the best actor on set). Butler used to know how to act, but for the last decade he's been letting it slide - I blame "300," because with so many fanboys telling him how awesome his totally over-the-top performance in that was, he's stuck with that roaring, swaggering model ever since. And Coster-Waldau is definitely capable of better than he delivered here - although the script is bad enough that I can't entirely blame the actors. I imagine that trying to fight and act on stilts may also somewhat reduce the quality of your performance. I suspect the director (Alex Proyas, who once looked like he'd go on to be great ...) spent a lot more time on the imagery than the performances. I'm a little surprised this thing made it as high as its current (2016-08-07) 16% on Rotten Tomatoes.