Oh, I totally understood the flavor was "cartoon pricked by thorns jump" once I actually stepped into it. Thing is, I just avoided the dead plant for a little longer than I care to admit, feeling uncertain of what to do. To introduce its mechanic, I'd consider having an immediate "dead end" at the start of the level, where it's just like a little cliff in front of you with that plant, so it's obvious.
But take that with a grain of salt. I'm not very good at platformers.
I know you didn't make the water sound effect; it just sounds a bit like some sort of sci-fi warp zoom to me, though I do think it could help to have it trigger less.
The music track changing as you switch dimensions is very cool! I'll confess I didn't really notice, but I just went back to check to see what you mean. I think something you could consider there would be changing the "vibe" and instrumentation of the track between worlds (and maybe soften or adjust the world-changing sound?) but again, take it all with a grain of salt.
Still very nice work!