Thanks so much to everyone who commented! For some reason I didn't get any email notifications saying people commented, and I didn't expect anyone to see the game, so I didn't even think to check!
PICO-8 is a bit of a special beast, and the PNG images actually contain the entire game within the image. It's super neat! That said, I should have also uploaded it to the website so that people could play it without needing to own PICO-8, I was just a bit hesitant because I didn't have confidence in the game. So, sorry about that. I've gone ahead and fixed it, so you should be able to try it now (keep your expectations low, haha). Thanks for taking the time to comment and care, and for giving me the incentive to keep up with it!