Nice game with great graphics and music.
I have been playing and I found a bug that seems not to be reported yet. In level 2 when I collect the keys needed to open the three doors of the first screen they don't open. I played in a real breadbin C64 with Kung Fu Flash (tested with the crt and d64 versions).
To finish level 2 I had to use the first key I found with the first door of this screen. When I came back with the two keys left the rest of the doors can be opened without problem.