Good concept, and having to time your level swapping to block enemies from chasing you adds some depth to the gameplay.
That the enemies can't kill you and only block you from moving could also potentially be used as a mechanic, as you could use them as platforms. Perhaps certain enemies could either move or remain frozen in place depending on the level colour.
The movement could be improved, particularly the floaty jump. There also seems to be a collision issue when collecting stars, sometimes the collision behaved the same as a wall, preventing the star from being collected.