This is a very low budget film and from the start you should not expect high quality fx - a lot of the rat scenes depend on fairly dodgy CGI work. And don't expect too stable a plot concept - (SPOILER!) mutant rats bred in lab research with a telepathic link to a human, and apparently an infective bite. But it does jog along quite enjoyable and doesn't outstay its welcome. The cast do a good job, and it's nice to see Ron Perlman without a stack of makeup and fx obscuring his face. There are some gross moments, but I wouldn't describe it as especially scary unless you have a fear of rats, but I've paid more for far less adequate entertainment; I'd pick it over Jonah Hex, for one. The sound quality is rather poor, though, I had trouble picking up some dialogue and there are no subtitles, so if you have hearing problems I wouldn't bother.