How bad is it? Most abhor this as full of cliches, but I think it's an homage of sorts.
Should you see it? You could do worse, especially among Full Moon films. So... yes.
Full Moon pictures, under Charles Band, has released a ton of terrible films, many of which are making it onto this blog. This may be among the best of them. It follows every standard idea of horror films, starting with the horror movie within a horror movie and the idea of using a real dead body in making a zombie film. In this case, a body on a mortuary slab reanimates and there's a portal to a netherworld of zombies. Everything follows exactly as one would expect, but it's not badly done; if you don't habitually watch these kinds of films, you could enjoy it and, if you do habitually watch these, you can have fun spotting the influences and guessing the next thing to happen. The film is a continuous stream of in-jokes, but the humor is dicey... and the gore is not! There's only a couple of monsters, only a couple of death scenes (poorly done) and not much atmosphere, except for what was stolen from Italian gore directors. It's hit and miss. I thought it was okay.