It took me about 15 minutes to figure out what I had to do, but once I did I did find the concept to be pretty interesting, though not being able to see the faces of the cube on the cube itself makes rolling it around pretty confusing. The instructions are also vague, so I had a pretty hard time understanding what was really killing me (especially in level 2) or what the icons on the cube's faces do.
All in all, a pretty interesting puzzle game which would really benefit from a better presentation.