Nice little game. I like the art style and the general game idea. Even though the mechanic is easy go grasp after a bit of try and error, I would recommend to add at least a short description at the beginning. The text which shows the power-ups should not be affected by the "lights out effect". Probably the easiest way to achieve that would be to place it in a separate scene. Some music and sound effects would also improve the game quite a bit.
Congrats to this game! I think it is a good start, but might still need some work.