This game doesn't appear to be NTSC compatible. I can't say that I'm not disappointed.
Try it on an emulator in PAL mode - problem solved!
Yes, I have been able to play it this way. It's just that I like to have the option to play the games I buy on my real C64. Up until now, all of my Psytronik purchases have been playable on my system. I'm just disappointed that this one doesn't. My fault, as I should have known to make sure the game description said NTSC compatible. But, I didn't this time. So, I left the comment above, in case others are looking for NTSC compatible games.