I've tested it on my real CPC6128 and I have the same problem. I have examined the code and there is a bug in the keyboard scanning routine. The same bug is also present in one of Leosoft's other games, Druid and Droid.
Oh no, that's really embarrassing! Thank you very much, Nich, I thought I had corrected the source code of Druid&Droid, but apparently I didn't (I copied the scanning rioutine directly from there...) I will upload a fixed version, once the contest is over!
