How bad is it? It's a pretty typical slasher by people whose pedigrees suggest better.
Should you see it? No.
This film has a lot of what made Halloween famous, was filmed a year earlier, but released later; what it lacks is quality, despite several people involved who were partly responsible for "Night of the Living Dead." A killer in army fatigues is killing high school majorettes; there's a plethora of red herring possible suspects and the real killer has no motivation. The film changes direction midway from a cut-and-paste slasher to a revenge film and it's messy and disorienting. The death scenes are poorly done, the dialogue is substandard even for the genre and the acting is universally wooden - it's like they filmed a table reading of the script. There are a few bits so bad as to be amusing, but too few.