“And, for a bit of fun, you can even play the classic game of snake by simply typing snake in the command line.”
Five years of work produced a kernel, process and memory management, a file system and a Bourne-style shell for a teaching CPU almost nobody uses. It will never ship to a customer. The person who wrote it now understands computers better than most engineers who list “systems” on a resume. That is the point of a hobby OS.