Why use uncommon d81 disk format if the files fit onto a common d64 image?Oscar64 generates much faster and smaller machine code from C, worth a try.
You're absolutely right! Before optimizing it, it didn't fit on a d64, which is why I used a d81. I'll be uploading a d64 version soon, and that's exactly why I created a slim version. Thanks for the heads up, my friend!