OK, there's 4 links.

2 of them have been dead for years; I can't comment on playability. (One of them appears to not build on Linux, the other one apparently does.)
One of them is expanded in scope, as you point out, and apparently on account of that still not ready.
But the fourth, Nova, seems to be what you're after, except multi-player. So all you should need is a bot. And no porting needed, even.

Edit: And Nova is in active development, too. Always a plus.