I picked up the Windows version of this as part of the Bundle for Racial Justice and Equality, and I think I've found a bug in this level in the Sand Cavern area:
After clearing out the enemies and destroying the sand blocks, I went to shoot the gems in the proper order, and after shooting the fourth and final gem in the lower-right, the game crashed and gave me this error message:
I couldn't find a contact e-mail for the author, so I'm not sure where to send a bug report; I figured I'd try posting here, though.