OK some more suggestions:
1) the music in the caves is terrible....
2) the lava/fire tiles could use some color cycle effect so that aren"t static!!
3) how about a "start" loading screen??
I managed to finish it using invisibility cheat..
Poke &47AE with &18 instead of &20 originally.
Warning: if you fall down you may need to deactivate cheat in order to continue the game.