I felt that 90% of the levels were easy, and some 10% were difficult. Despite the difficulty level, I did not enjoy the gameplay as everything felt bland.
At first, I enjoyed the art style, but as I continued playing, the music, the art style and the gameplay felt "basic" with nothing to spice it up. The biggest crime is the gameplay which made the game feel awfully slow and the game's purpose felt like it was to walk around in weird gravity, rather than solve puzzles.

If you still want to play the game after reading so far: look at 10-20 minutes of gameplay. If you imagine the whole game to be the same as what you have seen and the game won't evolve (either in music or in harder & interesting puzzles) then don't buy the game.