The opening hook is a real grabber. In fact, the movie's best scenes are the action among the other-worldly rocks and spires. 'Other-worldly' is apt since a caped figure called the Phantom Killer occupies the rocks with a deadly rifle and a shattering scream. So Ken's got a lot to contend with, since he doesn't even know his real identity or why cowboy Sykes and his gang are trying to kill him. Plus, just who's side is the Phantom really on; first it seems one and then the other. Good thing Ken's got Tarzan, the wonder horse, to help. And what matinee hero would be complete without a cute girl helper trailing along (Parker). Oh sure, it's standard matinee fare except for the creepy Phantom angle, and a couple of plot twists. At the same time, credit outstanding cinematographer Ted McCord for many of the complex scenic compositions. He later graduated to a string of A-productions including Treasure Of The Sierra Madre (1948). Unfortunately, my DVD copy had a lot of fuzzy sound, a consequence I guess of the many copies in circulation (IMDB Trivia). Nonetheless, the hour amounts to matinee time well spent and with an unexpected ending.