The Natural Selection 2 Website has patch notes for a new build 154 of the alpha version of Natural Selection 2, which is available to customers who have preordered Unknown Worlds' upcoming action/strategy sequel (thanks joao). The new version, which should be available through Steam, adds Havoc physics and significant framerate improvements among other things. The full change list follows.

Technical

• Changed collision detection to use the Havok engine
• Optimized trace ray and sweep capsule tests
• Fixed bug where keys could get stuck down after a frame hitch
• Fixed bug where players could not be removed from the scoreboard after they left the game
• Fixed bug where bots would not be properly removed from the server
• Fixed crash on exit when trying to run the game without Steam running
• Fixed bug where particle systems weren't properly occlusion culled
• Fixed hardware cursors not being properly released on shutdown
• Fixed bugs with the occlusion culling system not properly determining if something is visible
• Changed the "Couldn't Connect" error message to be more descriptive
• Added net_messages console command to log network messages received
• Added r_gui console command to enable/disable drawing the GUI
• Added the ability to include PROFILE markers in script code
• Added support for Lua GUIs on models (i.e. ammo display on the Rifle)

Gameplay

• Completely re-did marine, alien and "shared" (waypoints, chat, death messages, etc.) interfaces in Lua (was in flash). You should see noticeable frame-rate improvements.
• Added very basic bots for load testing ("dev 1" at server, "addbots #" or "removebots #"
• Armory "buy" menu fully client-side now so it's much more responsive
• Hydras now build smoothly
• MACs and Drifters now cost energy to produce (further eliminating spam and overly simplistic defense)
• Sentries turn off completely without power
• Power nodes have almost-dead and dead electricity/sparking effects
• Reduced number of network messages and footstep sounds dramatically
• Networking optimizations
• Power nodes work on level change
• Structure flinch animations fixed
• Changing weapons as marine is now faster and more reponsive
• Added basic pathing for bots (when commanding)
• Fixed MAC welding effects
• Skulk leap now requires research (on the Whip, coming soon)
• Fixed "doubling up" of some sounds