Current version of this game in the tree is 2013.02.03 which is a few years old. Version 2013.04.04 is out which appears to be new maps and bugfixes.
I tested the new version by bumping the existing ebuild in a local overlay. The patches in the files/ directory still apply cleanly. The SRC_URI has changed slightly (the version component is now "2013_01_04" instead of "2013_02_03") but after fixing that I was able to install it and play a bot match.
Additionally the ebuild in the tree is old and still uses games.eclass and installs things to /usr/games. I could probably write a new ebuild, hmm...