NS2 is currently under development, initially only a Win version will be available. This entry is for testing this version only, since Unknown Worlds Entertainment plans to release a Mac and probably Linux versions after few months.
Update: 01/11/2012
NS2 1.0 has been released and they still plan to start the work on a Mac version soon but they didn't have a road map yet.
Update 16/03/2013
The game now seems to work on OS X 10.8.3, lastest NS2 update and Crossover 12.1.2, you can see all 3D models.
See the other Tip "NS2 1.0 on CX11 Mac" for informations about getting it running while we wait a native version.
Update 04/01/2014
Sadly OS X version is on hold, Linux version is released.
Update 22/07/2014
The game seems to runs fine on OS X 10.9.4 with WinXP bottle, no issue to report. It is quite slow.