I am one of the original testers, and pleast forgive me for the straight forward nature of my remarks. It's a shame that multiplayer is not being worked on but there was a need to improve it anyways. The models looked nothing liked the single player, meshes or animations. WHile the game play was glitch fast at 40-60 ticks there was serious need for more enemies and special effects in the multiplayer version to meet the look of the single player version.
While as a serious gamer I understand your need to focus on the core project, please bring back multiplayer as it's seriously fun on Linux. One of the few indie titles that can be played peer to peer co-op destroying the same swarms would be great.