The game has a lot of potential, and I play it quite often now when I need a break from ESF. I say potential because there is plenty of room for improvement. The gameplay is repeticious over time, and it feels a lot like counter strike... with aliens... and a powerful guy telling you what to do. It isn't bad by any means, and I find it absolutely miraculously magnificant for a beta 1.0 . The gameplay is fresh, and it is amazing how balanced they managed to keep the Marines and the Aliens even though they are completely different in every concievable way. I can't imagine how many hours they've put into game balance, but it's more than impressive. Once 1.1 is released (should be about a month, maybe two) the game should pick up an even greater fanbase, with some new features and fixes for each of the surprisingly small number of bugs (for a beta 1.0... I mean DAMN I'm amazed how few bugs there are).
Once they really get into it later on, like around 1.2 or 1.3, and they start adding new aliens and extra features, this game will really take off. Until then it's a solid waste of time, but the jet pack/hmg and fade rushes do get old after a few days. This would be a good one to invest some time looking into.