I stopped many years ago. I was working on it in between sending out job applications, I was happy to gain experience working on a code base larger than I felt comfortable reading and one that is ugly but a rewrite is not an option.
I didn't add too many features, I was mostly reducing the amount of compiler noise and fixing any bugs I ran across.
I'm currently having lots and lots of fun playing this game (experimental builds). It's pretty much halfway there to Dwarf Fortress...