I can't understand why Zack Snyder didn't direct this sequel, and how someone who has never directed an action sequence before and just one feature film can be entrusted with a production of this magnitude. That would already be a recipe for disaster, even though in reality Snyder was supervising.
In an attempt to live up to it's predecessor, 300: Rise of An Empire is action-packed, presents impressive visuals and is very bloody. In fact there is more action, more blood, and more nudity than in the original 300. As for the plot, there really isn't much to chew on. A naval commander, Themistocles is supposedly trying to reunite Greece. Since the story takes place before, during and after King Leonidas leads his men to fight the Persians, it can be hard to follow at times.
Most of the acting was mediocre and couldn't quite compensate for the weaknesses in the story. The Australian actor cast as Themistocles in my opinion was a very bad choice, and comes nowhere close to what Gerard Butler did as King Leonidas in 300. He just doesn't bring that rugged heroic presence on screen as is expected. Interestingly I read somewhere that director Noam Murro insisted it would be Sullivan Stapleton who played this character, claiming he was 'the one'. Eva Green on the other hand is plays an excellent villain as Artemisia.