This is an awesome puzzle game, one of my absolute favorites. The graphics are really cute with attention to detail, and the soundtrack contains some of the best music I've ever heard on the C64. Especially the fast tracks fit the time pressure perfectly.

The rules are totally simple. The difficulty increases slowly and gets pretty hard around level 50 or so. I'm on 64 now and looking forward to more challenges :-)

(I'm playing the .d64 on an Ultimate64.)