How bad is it? Typical cheap 1980's horror, with some style.
Should you see it? Yes, but not because it's so-bad-it's-good.
Five young people go to Alcatraz to stop the spirit of a cannibalistic cavalry commander - the explanation of why there, why them, why now is confusing - but one of them is taken over by its spirit. There's a severed hand, a ripped-open torso, a human barbecue, worm vomiting and a punch through a skull. Hope Marie Carlton removes her shirt several times, as that's what she does. Devo contributed a song to the soundtrack. Toni Basil ("Hey Mickey") plays the ghost of a rock star responsible for unleashing the spirit (don't ask). The plot makes little sense, the acting and dialogue are below par - the star is the son of a co-executive producer - but it looks good, it's fast-paced and it's just weird enough to be entertaining.