I think this movie is more than an MMA one. In some way remembered me the show Kingdom. This movie have a great heart and a soul too.
First, Stephen. D is great here, probably his best perfomance in years, he is authentic, raw, brutal and cruel. Second, the script is good enough even you have seen similar stories before like the mentioned Kingdom show. Predictable but enjoyable. Last, all the cast including special actors are great making overall a great job.
To sum up, if you like shows like Kingdom, this one is for you. Enjoy.