A alien got to earth and infected the water and bringed to him other alien species like Bullsquid's Barnacle's, Headcrab's and Vortigaunt's.
You are in a water factory, trying to kill the alien's even the alien boss.
The military have arived but they are to scared to let infected's spread they're viruses so they want to kill all humans from there, that means that you have to kill the too.
You need to escape before the factory blows up so good luck.
