This game has a neat core mechanic, and my favorite part is the visual design surrounding it (i.e. your character, the dungeon theme, and especially the ghost). Rocket jumping was a fun twist to the usual puzzle-style game.
Although I liked the ghost mechanic, it felt like every level followed the same method. Grab box -> set box on button -> stand on another button -> die -> run to end while ghost does the work. My favorite level was the one with no spikes, because instead of immediately killing the bat, it forced me to avoid it long enough to press the buttons and then purposefully jump into it. Little variations like that keep levels fresh in this sort of game. However, to keep things interesting I think you need to introduce new mechanics. Maybe there is a "holy light" the ghost can't enter, which forces you to do part of the puzzle in human form? (This idea is shamelessly stolen from this game, which has a similar theme: https://itch.io/jam/wowie-jam-3/rate/939818)
The movement felt a little awkward because you move so slowly horizontally, but when you jump you move up so fast. I think bringing the two speeds closer together would make the controls feel more natural.
Overall, this game is based on a great idea with lots of potential, and it has nice visuals. Great job!