KF 2 just had a recent update. I'm not sure what it did but now I can run KF 2 for Win 8.1 >.> I was having issues trying to even run it on my new comp. If KF 2 hasn't worked for you (seeing as a lot of people online have had issues with KF 2 not starting up at all), try it now
-Mandalor
New Perks
Firebug
Demolitions
Berserker- completely reworked
There's been updates to the Perks as well as new weapons. It's a massive update.
There are currently 6 maps now in KF 2. KF 1 came out with 5 core maps (but they came out periodically with at least 3 new maps every update that came very couple months). They might just be done with making maps for the game.
They're probably pretty close to finishing the game come this December. I'm actually surprised and I'll probably be playing it more. Just a heads up, they will not be erasing perk xp when the game is fully released. So don't worry about loosing anything :p (at least that's what I've been told from a trusted source).