That's exactly what it was, I had downloaded version 1.0 without realizing it was PAL. Grabbed the 1.1 and it works perfectly. Many thanks, great game!
There are no enemies to kill. I can't backtrack because I'm at the very beginning. If I go left the screen won't scroll ('cause I'm at the start) and if I go right I'm blocked by the stone. No enemies present themselves.
Can't make it out of the first area? There are no enemies and the way is blocked by a square stone. Checked the manual, didn't see any reference to it. Tried pulling down on the joystick.