Super-easy but cool
Level 23 is a little challenging. Every other level has an immediate, obvious "solution" that takes about 10 seconds to see. If it had more than one puzzling level, this could be a nice concept. Graphics are smooth and pretty.
One thing that would improve the difficulty level would be if you had a whole cube rather than just a 2-D hexagon projected as a cube. The topology of a real cube would add all kinds of interesting possibilities.