A really neat concept! It was fun having to time my jumps just right in order to avoid touching the wrong cubes. I also enjoyed the mixture of the 3D platforming space with the 2D player sprite. I think the biggest thing holding it back is the physics/collision systems. The jump felt kind of wonky, sliding on the walls often pushed me in an unpredictable direction, and it was often hard to tell if I was going to collide with a block or wrongly colored tile. The UI could also use a little sprucing up too (maybe use a pixelated font like you did for the start menu). But otherwise, I enjoyed the graphics, the use of multiple music tracks, and the concept overall.