Fun, creative level, like how you kept the very vertical nature of the original 5-8 and the difficulty too. Some lag issues I noticed (cause of Super FX sprites gah):
Too many Super FX sprites at once causes some lag, maybe try spreading out / reducing a bit.
A couple suggestions you could maybe add:
Punish the player for bouncing all the way to the ceiling using the trampoline, put some of those spikes here :3
Might be fun to put in a hidden 3 or 5 star cloud on one of those clouds or even up high, above where my Yoshi is hovering. Since you don't need eggs for Raph fight, may as well reward player if they come with eggs.
I want to hack Raphael in some way, any ideas? Post em here or in my "Boss Ideas" thread.