I unfortunately got stuck at the level with two vials :( Ghost wouldn't go to the top platform. I really enjoyed it though, this has a lot of potential as a little puzzle game. The art, the game mechanics, the audio, all of it felt really cohesive.
For constructive feedback, some of the stages require quick timing, like standing right below a ghost, click the switch fast enough to get him to come thru, but not kill you. This was fun for me personally, but if your goal is to be a broad accessible puzzle game, this might box out players who don't like reflex tests. Introducing this type of mechanic can also sow doubt with harder puzzles, players may completely miss an intended solution to a puzzle and think they're just too slow at quick flipping levels to glitch ghosts thru floors or something. Not a big problem, you definitely keep this and it still be a great game, just trying to be constructive instead of giving only compliments :P