The level design is great, 6 levels in each area and 24 levels in total. Each area has specific connection to the other area and each level of area must have connection to at least one of the other level of an area so it won't make the player get stuck.
The only thing I think a little bit confused is the rock collision while level changes. Sometimes the rock will slide away when the level changes, while sometimes it will has weird collision and won't slide away with the level. (I don't know is this situation is supposed. Since I don't know how to get one of the brown gem in the blue area with wall blocked and eventually I stay in the red area, let the rock stay at the blue area in the previous level. Then I switch the blue level and using this wierd collision to let the rock jump onto that floor so that I can clear the wall.)