Marvellous title, fabulous concept... And some of the most wretched excuses for characters I've ever seen in a film. Five minutes with the trio of vapid, whining college girls, and you'll not just be siding with the undead rodents [are beavers rodents? Note to TC intern: please fact-check this before publication, then get back into the dungeon], you'll feel that having your face chewed off by a psychopathic animal would count as a blessed relief. Then their boyfriends turn up and, remarkably, things get ten times worse. You will need enormous fortitude to sit through the first half of the movie, until the beavers show up in significant numbers, and things improve significantly, purely because the humans shut the fuck up, realizing they have far bigger, more aggressive problems than who slept with whom, or how long it has been since they last had an orgasm. Of course, part of the point may be deliberately making them unlikeable, in which case this is the greatest piece of cinema since Citizen Kane. But if so, five minutes would have sufficed.
This almost sinks the film before it gets going, yet it is somewhat salvaged by an enthusiastic second half which proves the beavers are not just unstoppable, a mere scratch will also transform any affect human into a similarly hungry, buck-toothed, flat-tailed monstrosity. [This incidentally leaves the inevitable post-credit, sequel-setting scene with a lot of questions, much though it plays into a personal fear] It's also worth sitting through the credit for the snappy, Dean Martin-esque lounge tune which accompanies it]. While there is some crappy digital blood work, the special effects for the beavers are mostly practical: it's not what I'd call convincing, yet that isn't inappropriate in regard to the obvious B-movie vibe for which this is aiming. As long as this is in motion, with the human characters sticking purely to running around and being gnawed on, it's decent fun. Whenever they stop and open their mouths, however, the stream of liquid shit which emerges will have you convinced you should have stuck with just the trailer.