Hi, I saw your post. I thought your idea was really original, and the sprites look great too. While playing, I also came up with a few ideas. One thing that could be really cool is if each keystroke played a rhythmic sound that synced with the background music. That way, typing correctly would naturally add to the melody, making it feel rewarding on its own. Another idea would be to have the letters burn away as you type them. I think that would fit the jam's theme even better, and it reminded me of that meme of the that guy whose ink catches fire while he's writing.
Since the game is fairly short, I tAhink adding a score system could give players an extra incentive to take on higher difficulties. It could also be fun to award bonus points for typing entire words perfectly without missing a single letter, something like a combo system.