The difficulty curve in this one is great. You go from dead simple to fairly challenging, and it feels like you hit all the stops in between. My one piece of feedback is that I think the theme could have been incorporated into the gameplay a bit more. Most of the time, the light and dark modes felt less like modes and more like separate levels (with the exception of the levels with the ghosts. They established that sense of persistence). I think maybe allowing the player to switch modes at will would have gone a long way in improving that feeling that these two modes exist in the same space. Other than that, your game runs great and its a fun little game. Great work!