Gorgeous work - both with the graphics and the audio. It's simply ... perfect.
The inevitable questions:
1) Am I correct in understanding this is PAL-only?
2) Any plans for a 2-player mode, or are you done?
Again - bravo!
This is PAL only because it requires all the height. Remember this is originally a portrait game.
2 player mode could be done but that adds some extra complexity (start 1 or 2 player mode, reworking scores/levels). There are really a few / none amiga games (including arcade ports) that support this alternative 2 player mode.