I have the best memory's of the original game (which was a halflife 1 mod, the 2nd game is stand alone), seriously no game has come close to the originality and excitement that game had. And it also has some pretty impressive stats to boot: had over 2 million downloads, and had been played for 2 billion player-minutes. NS2 can be had for as little as $30nz, thats a crazy price for what is going to be a great game..
For anyone that dosnt know, this is a Marines VS Aliens multiplayer only FPS/RTS game. Each side has a commander that has a top down view of the game, for the marines the commander dishes out orders, weapon & armour upgrades, buildings, medikits etc etc. Everyone else on that team is a marine with a FPS view. The aim of the game for them is to eradicate the aliens, the thing with this is its a resource management game as much as a FPS, control the resource points or your money trickles to nothing and you get no decent weapons to defend yourself, or tech upgrades to get higher spec gear.
The alien side is a different beast altogether, there are 4 classes of aliens each with there own abilities. They build hives which increase there abilities and unlock other extras for there side. They also have a commander (new for NS2) im not entirely sure what the role entails as it hasn't been made clear yet but it will be similar.
I cant empathise how awesome this game is! and cant wait to get my hands on it :)
Heres a trailer of the original game which demonstrates the play mechanics: http://www.youtube.com/watch?v=yJbR7wUoNBg&fmt=18
And a trailer for Natural Selection 2: http://www.youtube.com/watch?v=_H7prHUApzs
That trailer is done in-engine, only thing that's not going to be in the game is the Onos ducking under the door and the vents rattling on the door as its smashed in.