I've just finished watching this and can not recommend it highly enough. I've always been a fan of his previous work such as Spartan and Glengarry Glen Ross. It's a Martial Arts film at heart exploring such concepts as honour and loyalty but does so in an original manner. Quiet a few twists and turns along the way keep things fresh. If you're a Mixed Martial Arts fan (and I am not) then it's well worth a watch.