From what I've read he got interested in the engine that powers Nexuiz and used Nexuiz content because he didn't have a whole lot of stuff built at the moment.
"Just reading back here and missed one of your questions. What's the project about.
Well basically, myself and Nik had been creating maps for another free FPS. We'd contributed them, and also contributed some game code and applications. We had a discussion and decided to set about creating a new open source game as a challenge.
After some deliberation, we settled on the DarkPlaces engine, and dropped in the nexuiz game data so we could get to creating content, and testing. It's so much more structured to replace content, than it is to anticipate what is needed. Hence, the Nexuiz models at the moment.
The game itself is going to have a futuristic feel, and will include standard game modes such as CTF, Deathmatch, etc. but will also include a "ship" mode. In this mode, you take command of a ship and battle against the other team in dogfights etc. Can't say too much about that at the moment.
Hope that answers your questions.
Davey"
More on this link:
https://trinity.gtxstudios.com/forum/topic?id=39#p155
ECKZBAWKZ HUGE LIST OF ACHIEVEMENTS GOES HERE....
Oh wait.