Found it to be an enjoyable movie with a couple of weak characterization moments. Wasn't bothered with the embittered soldier back story at all really, more with the heel-face turns some characters make and how they're played out.
I rather liked the ending of the movie.
The Therns should've been handled differently, a bit less powerful and the whole movie would've made more sense. Say: they would be able to influence people but be physically intangible, that way there'd be a reason why they'd seek to mess around with others instead of having all those loose plot threads dangling explanation they came up with.
A number of really imaginative vista's, straight out of those old sci-fi paintings (RIP Mr Frazetta and Giraud). I'm a fan of Don Lawrence 'Storm' comic books, strange to see how closely they resemble John Carter. Still, sailships pendeling between a mass of planets at the edge of a white hole gives some other possibilities than simply being on Mars does.