I had a quick look at the big match expressions, and this does not look like this project has been through cargo fmt (it would add +2000 lines of code for the whole project). Which is probably a good choice, but as someone who's been looking at this, I wonder if the tradeoffs made in rustfmt are the right ones (note: I have no idea how I would make this better for the general case).
I'm working on one too! Just got to the milestone of being able to scroll the Nintendo® logo. I refer to rboy a lot, it's been helpful to see another implementation.