I don’t know if the free version is a troll or simply badly programmed. I thought I got how it worked in the tutorial, but then in the actual game the numbers displayed seem totally random and I don’t know what to press even when I can tell the pitch is different. Also, the enemies close in way too fast from all directions so there is no way to survive for more than a few moments even if I could work out what button to press. So completely unplayable, whether by design or not.