its the paintball mod that was talked about a while back. It may have been posted on the boards a while back, but here it is again if u havent seen it. All u need to play is a computer (duh), half-life, and the download at that site. Counter-strike started out exactly like this game and is now the only half life mod sold as a serprate game, and millions play it. THe game still needs a lot of polishing, but its in its early beta stages.
edit... cs retail sux lol, but u can use it with this mod.
ive had the game a while, and actually a few friends who had quit pb started playing again because they played that game. its pretty cool but still has a lot of bugs and needs polishing but is still a very fun game. If u have questions pm me or post here, and ill be glad to give help if u want it.