If there was ever a mis-titled film, this is it. Hell High does involve high school students [Although they are Beverly Hills 90210 High School students who look about 25-30 years old!] But the focus is really on the Biology teacher who witnessed a traumatic event in her childhood. When she students start to bully her, she looses her shit and goes on a killing spree. [Trust me, her victims deserve it.] So a better title would help because I was expecting this to take place in the school but very little of it does.
Hell High is predictable slasher stuff with no creativity whatsoever. You see everything coming from the beginning of the film. Yet, this does not mean it's a poorly made movie. In fact, one-time-only director Douglas Grossman does a better job than some veteran directors who have multiple movies attached to their names. He makes this movie work given its limitations.
Therefore, it's not bad but its not good either. In the end, its simply uninteresting. Given the plethora of Dead Teenager movies that were spawned after the success of Friday the 13th, there are too many other great options to watch if you're in the mood for this kind of hour movie.
For more info check out the film's entry in IMDB.