A top secret space expedition to Planet X results in the crew being killed by the giant rats (complete with glowing red eyes) that inhabit the planet, and the only survivor, Sonja, is able to make it back to earth but brings some rats back to earth with her and is also being controlled by a space rat that crawled into her brain through her... ahem... nether regions, and she goes around eating everybody.
A great deal of the movie then focuses on Sonja, who is unable to die, and her condition, and the rat leader inside her brain looking to lead his "people" to taking over the world. This gives way for an incredible finale where the giant rats rampage through the city and cause mass (and I mean MASS) destruction.
Everything about this movie: bad acting, hilarious special effects, gore, giant man-eating rats, action, explosions, miniature models, all work together in perfect harmony to make a highly entertaining bad movie.
One thing I found comical was that in the place of actual buildings and locations we have miniature models, and in the place of vehicles we have remote-controlled cars, with the drivers CGI'd inside. Also, instead of CGI rats, all of the rats are either real rats put inside the miniature models I was talking about earlier or life-size puppets, which I really appreciate. I don't know what it is about model miniatures with me, but it just works.
Some scenes in particular that stick out for me include the rat breaking out of the woman's head, and a car commercial with stop-motion rats (probably an homage to the KIA Soul hamster commercials) that had me cracking up.
Review by TheRetardedVacuum from the Internet Movie Database.