I just noticed that Litil Divil is on GOG! I remember playing this something like 15 years ago, but I never managed to finish it: there was one room on level 5 that I never managed to pass, involving a trampoline on a demon skeleton. Supposedly you had to run up to the trampoline and press the jump button just before hitting it, but it seemed utterly impossible to get the timing right. I more or less concluded at the time that something about my system at the time was interfering with it, probably because the system speed was so much faster than the machines it had been designed for.

Has anyone played this and gotten past this part on a modern machine? I'd like to try finishing the game if it's actually possible.

It is possible to clear the trampoline room, I beat Litil Divil a few minutes ago. You have to stand at the edge of the screen, just a bit above the backbone, where the pink stuff alnong the backbone is. Then, you have to press UP + RIGHT + Z and hold them down. Mutt should start running. You'll know if you did it right as the Devil has different animation for running. Then, while still holding the buttons down, you have to press X before you reach the trampoline to jump at the skeleton's teeth. You have to repeat the action a few times.