I like to mod source engine games.
After explosion of citadel an Combine SWAT unit still alive..You must go and try to kill Mossman and Destroy Ultra Gun until Gordon get it.
A war of humans and zombies in cs2d... destroy zombgz!
Your mind is damaged. You were sent to Hospital. Two weeks later zombie infection began. You must escape from Hospital. But your mind and zombies won't...
This mod takes place 23 years after Portal 1 where a "VP Lab AI" is controlling aperture science.