Comb through and make sure that the player is not able to get above the ceiling of your levels, you could try something like this patch here! (though I'm not sure how it will go with your cutscene areas)
My other major issue with the hack was slowdown, particularly in the later worlds: This screen here for example is moving at a slugs pace, despite not much going on.
I do have a theory as to why this is happening, and I believe that to be related to your sprite vertical spawn range. Go into Lunar Magic, click on and there should be an option to customise that. The taller your spawn range, the more sprites you're gonna have out and about, which can be a problem for taller levels like this.