I updated the sprite for evil Die Guy. I also have an updated sprite for normal Die Guy that makes his mask look more like a Snifit mask (he's a Snifit) but it's not in the project.
Press the green flag to hear the boss theme. In the backdrop I also added a sound for a "confused" or "distorted" version of the song. If you add vibrato to your Jummbox instruments, and press the down arrow next to the word "vibrato", you will see a slider called "depth" under the vibrato drop box. Adjust that to add a confused effect to your instruments. The purple stuff on Die Guy and Shy Gal is supposed to be a visual effect of the curse. My idea was that Shy Gal ran off with Die Guy to try and turn him good, but was instead cursed as well.