Sometimes all it takes to make a good thriller is take away one little security of human existence we take for granted. In a very different type of movie, A Nightmare On Elm Street did that by making it fatal to fall asleep. Tremors, which is more of a creature feature than a slasher film, makes it dangerous to touch the ground. It takes this simple idea and runs with it, having as much fun with it as it can. The result is a guilty pleasure: featherweight but chilling and funny.