This game has already been out for a long time. xD I won't play it again because I've destroyed it, but just here to say that it's amazing. The difficulty is greater in this one as well.
This version is so much worse than the last. They did what most developers who just had a smash hit do; they overcomplicated the follow-up. Simple is better in some cases.
This is (by far) the most boring of these shooters I have ever played. You can't see near enough, and your weapons absolutely suck. The game is do-able, but nobody will want to actually do it; if you get what I mean.
Once you get the M16, you win. Simple. Once you get lazy, just buy an assload of Prometheus bots and put them everywhere at the beginning and at your main wall in the back. Then you win every time, and you don't have to click a thing.