I just got done playing Alien Arena 2010, and after about a half hour I uninstalled that garbage off my computer. The game is absolutely terrible. It's about as much fun as watching paint dry for 12 hours. The game is extremely buggy, to the point where it's almost unplayable. Very few people play the game online too. The graphics are absolutely terrible, but that's not really a big deal to me. The sound and music for the game is terrible. The weapons in the game suck. The game suffers from massive frame rate issues, and the gameplay itself is generic at best. The spawn points are completely messed up, for instance you spawn right next to the enemies in FFA, literally. If anyone is interested in trying to see for themselves, you can download the game for free here: http://icculus.org/alienarena/rpa/
...try Alien Swarm. It's fun with some Steam mates and a mic. But you do need to be on the same skill level more or less, or certain members fall out directly, and it's really a team game.
i've try alien swarm but i haven't tired this alien arena is this a similar game?