Pandemonium really tries. I mean, it tries HARD! Come to think of it, that might have very well been it's problem. The cast is certainly up for the challenge and they frequently make things funnier than they probably were on paper. There's a few inspired moments, especially a scene where Eileen Brennen and Carol Kane re-inact a scene from Carrie. It's a great set up and the basic plot would make for a great slasher film. It predates Scary Movie by nearly 20 years and has a slightly more over the top and jokey feel than the previous years horror spoof, Student Bodies.
It's a shame Pandemonium isn't as good as it could have been. There's so much going for it and so little coming out of it. If you're a fan of one of the actors involved or a completist, you might get a kick out of it, but it's mostly unmemorable.