High School Heroes is a testament to the idea that "less is more." This doesn't apply to the violence, the film is extremely violent from beginning to end, but the details of the botched diamond heist, which the entire film is based on, are conveyed only in the dialogue, except for one scene where Mr. Pink (Issei Kanasashi) recalls his escape. The whole film takes place after the failed robbery is over, and the mystery that unfolds among the criminal participants is amazing to watch.
This is not a normal crime film. The thing that really sets High School Heroes apart from all of the others is that it is PURE. When you look at the screen, you're looking at reality. There are some Toei actors, there's no make-up to make them look pretty, there's little to no comic relief, and most important of all, there's no goofy romantic subplot clumsily thrown in, a detrimental trademark of so many action films, as well as virtually all Sentai films. Instead of all of that garbage, Toei decided to just present the film as simply and straightforwardly as possible, and by doing that he makes it seem that you're really looking at a bunch of criminals trying to figure out what to do after a suspiciously failed robbery.
Even though most of the actors were known at the time this film was made, the film was delivered in such a way that you don't see the actors at all, you only see the brutal characters that they portray. It is genuinely frightening to imagine being in the same room with any of them, and this is a quality that is rarely achieved in any kind of film.
Make no mistake, The High School Heroes is among the most violent films ever made, and some scenes are really painful to watch, but the way that reality is captured is something that justifies the violent excesses in this film. The violence is never glorified, nor is the criminal lifestyle. When films are overly violent, they usually get branded as such, but despite the extreme violence, The High School Heroes still manages to deliver an important overall message about the consequences of your actions. It remains high on the growing list of Toei's classic films, and it will not be soon forgotten.
