Hey all, glad to see so many of you enjoying the game!
I forgot to mention but if you have any questions I'll gladly answer them.
Space Guy.. in the current game modes (DM and CTF) your skills reset at the start of each round. This is for balancing purposes and it also adds a bit of strategy to your skill build based on the map and what other players are using each round. There will be another game mode called WAR which I'll release as v0.7 where your skills will be permanent, which should be pretty cool - much more MMOish. The gamemode will be somewhere between BF2 and DoTA.
JJA0, a few people have mentioned Rambo mode before so it seems like a pretty popular choice. Also zombie mode gets suggested a lot. Next version (0.6) there will be a racing gamemode, too.
Anyway see you in the servers! More feedback is welcome :)