It's working great on my Win32 starter Nvidia Ion system now. :) I noticed that the game doesn't seem to save if you click 'Exit' on the score screen after completing a stage though, which is strange. You can win Highland I and then exit, and it doesn't unlock Floodplain.
Damn! Thanks for pointing that out. You should still be able to press continue in the main menu to get back to the point just before you finished Highland
