Just want to tell you about
this game I found on Aminet. Here you have good platform engine there you can pretty much change everything!
You can very easily create objects, levels etc with the included editors. The title screen, ending screen is also easy to modify (iff images). And the music is in Protracker format. What i can see, there is nothing you can't change
Maybe something worth to check out for AmigaPD, nittamituaki and others who have made great modifications for other games