Graduation Day is shit, too, and I'm left scratching my head at the relatively decent user rating on Amazon. To be fair, it's slightly easier to get through than the worst slasher movies, and there are amusing moments to be had unlike the entirely soulless Madman which I begrudgingly featured last year. As a bonus, you get to see Christopher George at the end of his career and Vanna White and Linnea Quigley at the beginning of theirs. Wikipedia claims the movie cost an estimated $250,000 and made almost $24 million at the box office, which kind of makes me wonder why Troma is broke all the time.
In the beginning they want you to think Anne is the killer. Then they suggest the principle, a security guard, and eventually implicate a classmate. When the movie finally reveals the killer, you won't care enough to be shocked. Meanwhile the visual quality is absolute shit, which is to be expected from Troma; they seem to have less knowledge about video codecs than a beginning YouTuber.
I'm glad I've finally seen it, just to say I have, but if you're not a completionist you'll do better to move on.