This is a movie that you can watch despite its non existent scenario and dialogs, because it is well paced and producer Roger Corman, in an early effort, makes every dollar count in production value.
But of course one checks it out because it is Jack Nicholson's debut movie. And yes, one already didn't have Jack Nicholson's voice, and yes, one already didn't have Jack Nicholson's face, but, yes, one could have easily acted as badly as Jack Nicholson then. Knowing what was to come next, this makes it worth an idle glance.