The movie is based on the Gods of Ancient Egypt. I know enough of the mythology to know that in different traditions that Horus or Set were married to a variety of different goddesses, and that Ra was deposed in different ways. These threads of the story line work reasonably well.
Similarly, the generic thief with a heart of gold, and poor girl star crossed lovers type thing rising up and deposing unimaginable power is pretty standard fare, and is handled well enough, if not well enough to make us particularly worried over the eventual fate of anyone. This is, in some ways the real problem of 'gods and humans' movies, should the audience sympathize with the gods, with the mortals? It is almost impossible to do both simultaneously, yet to a degree I think this is what we were supposed to do, and thus makes it difficult to really care much about anyone.
Where the movie comes into it's own is in the special effects. THIS is what I think a lot of us dream about as what Egypt (the myth, not the reality) should have been, and it is worth watching for these alone.
That said, sometimes you get the feeling that things are being shown and so magestically huge simply for the purpose of impressing the audience, and it just ends up being annoying.
If you want a fast paced action romp with good visuals, this is a movie you will enjoy. I think that if you liked movies as disparate as League of Extraordinary Gentlemen, or the much less loved 'I, Frankenstein', you'll enjoy this.
Suspend your disbelief, sit back, enjoy the romp!