Squirm chugs along nicely, builds up its quirky characters, has wit and flair, and some excellent creepy moments. And I actually like movies that knows it is a bit ridiculous without the director indicating that he feels superior to the material.
Jeff Lieberman, in his heyday often labeled as promising as John Carpenter and David Cronenberg, continued in this vein with the cult classic Blue Sunshine and the interesting slasher Just Before Dawn. Then all fell apart when he tried to go camp with Remote Control. The experience was so painful that he sadly quit movie directing until Satan`s Little Helper.
Final thoughts: If you go with small animals, make a small movie. Do not make The Swarm. (Ok - they did, and it is great fun.) Make this. Or Slugs.