It takes place in a mental institution, where the patients (for what I could figure out, mostly female ones) regress inside their subconscious and create their own world were they "fight against the oppression".
The movie is directed by Zack Snyder, known for 300 and Watchmen. Personally I adored 300, but I found Watchmen a bit to slow; as it turns out from this trailer this one shouldn't have that problem.
Also, it's basically pure artistic action/violence in it's most attractive forms: fantasy, war-zone, SF, gangster-style...and with some charming center characters. I guess that after the spartan muscle-sculptures more delicate human beings were called out to serve as entry magnets.
Anyway, I'll be looking forward for the long trailer, and probably the movie itself.