Pretty tricky game! It looks and sounds nice :)
I had a really hard time figuring out where the blocks were located in 3d space though. It also was a little hard getting used to the rotations of the cube. It rotates so fast that you kind of have to figure out by the resulting block position how the cube was just rotated. Maybe add a little image of the wasd / arrow keys oriented the same way as the level? That way you can easily see what button rotates the cube in the direction. That way players can focus on the puzzles themselves :)
Once I got used to it the puzzles were really challenging in a good way. Great job :D