Firearms is a modification of Valve Software's computer game, Half-Life 2. It's a realistic modification of the game, that focuses on teamplay with gameplay altered to the extreme.
Did you feel that Surface Tension in Black Mesa was lacking? Did you dislike the fact that there were fairly hefty cuts to arguably the climax of the entire game? Look no further, Surface Tension Uncut adds 40 - 55 minutes of gameplay to Surface Tens