I mean, all of those depend on how much was imported as third party dependency, how much was not addressed at all, and what was actually solved manually.

They're all doable if you focus on the core problems. He's got a github with many of the examples up, it's instructive on how to keep things small.

And I think it's important that (based on the code) he had a solid understanding of the problem space before starting to write code. You don't write that tight when you explore a new space.

Edit: https://github.com/ssloy?tab=repositories for the shortcut link :)