indeed this is the screenshot from No Mercy game, which was cancelled and this is the screenshot from multiplayer part of the game, which was supposed to be implemented.
From what I know this is the screenshot of Deathmatch mode up to 8 players.
Jason Ely promised us to finish up the multiplayer mode and adopt it for windows, since he had the code. But I didn't hear from him for a while. Goku (Keenan) has closer contact with him than me, maybe he can share some light on this topic.
I guess he is too busy with his project - http://www.stygianworlds.com