How bad is it? The video box says "Worst movie ever made?" It's bad, but not THAT bad.
Should you see it? Yes, if you can find it now that it's been re-released.
Like most people, I thought this was going to be in the Critters and Ghoulies category, by the title, but the monsters are secondary to the plot about an anarchistic punk cult. There's a bad girl fight with a knife-with-blood-cartridge involved and later there's a scene where someone loses an eye when they actually encounter the aliens, who just leave for no more reason than they arrived - but not before one gets beaned with a frying pan! There's a bad goth-rock band, there's WAY too much talk (the hero's pseudo-scientific talk is fun), and then there's a twist ending that will make your head ache.