First: the art is cute.
Secondly, the balance between light and ennemies is interesting. Ray of light are both reliefs and source of stress. And while ennemies can be stressful, their presence is often essential. It's clever.
My main issue was the random position of ennemies that could make the platforming too challenging. Sometime two ennemies at the wrong place make a jump undoable, and waiting for them to go away isn't an option...
But still, the game is managable. The difficulty is well balanced, with a level design that has some original ideas.