I think the CommonSense content summary above is pretty inaccurate. There is plenty of violence, no doubt, and a fair amount of blood. However, nothing takes it over the top for a mature 13-14 year-old kid. It really is the same amount of violence portrayed in various action movies (i.e. Casino Royale, Bourne Identity). In this show, it is better, because the violence is portrayed as what it really is: something atrocious, malicious, and terrible, rather than something done by a few careless bad*sses who work for the government, like James Bond. There is more language than the above summary lists; *ss, d*mn, h*ll, d*ck, and SOB are all used. There are also a few positive messages about how violence is very bad, and the main characters are very good people who work for the common good. The show is off to a good start; it could get better or worse (but hopefully better!).
As a final note, there are violent themes; all the escaped inmates are serial killers, child kidnappers, robbers, etc.