As someone who used to play Natural Selection 2 I suggest that you stay away from it. Here is why.The Good:
The base idea in itself is great. There is really no other game like it.The Bad:
Ever since June the development team has only listened to the extremely small and vocal forum community. The competitive/forum community has always wanted the aliens weakened and the game more complex. The problem from day 1 is that the game has always done a poor job at introducing new players to the gameplay mechanics. The gameplay is unique and complex so the game has always had a poor retention rate.
The competitive/forum community's demands have ruined the atmosphere of the game. It used to be so fun playing on both sides. Aliens were the dominant stealth team. Humans were the dominant raw firepower team. Now aliens are bogged down by low stamina and low maneuverability. The aliens' assassin class (Fade) went from being a night terror to Walter White's cancer from Breaking Bad. The game went from being a super tense game of wits to a typical blast 'em up game.The Ugly:
The development team has dropped all gameplay collaboration between any community. There is a thread[forums.unknownworlds.com]
on their official forums 19 pages long complaining about the new alien vision. This thread was started back at the end of August. The dev team finally responded to the topic at the end of November. That's a quarter year delay for a simple response to a massive gameplay change.
The dev team has gone completely rogue and continues to make game even worse and worse. There is a reason why this game is 90% off while only being 1 year old.