Hey! Can I just say that it's good to see the word "Project Gutenberg". Last time I've been there, I've read "The Turn of the Screw" for my Creative Writing Project in college and it was awesome to see so many free books there. I'm glad you are doing this to support the wonderful site!
So, visually and musically, this game is really good! The look and design feels unique and tbh, this would do really well as a Mobile game if you wanted to release it there. It felt a little overwhelming at first, but I settled into the rhythm of guessing and finding words and the font is lovely. The only feature I'd suggest, is maybe have a difficulty setting where on the lower ones, you can have a few letters already typecast. Other than that, this was really cool!