Diffusion

Diffusion is a total-conversion mod in its own universe, based on Half-Life SDK and running on Xash3D FWGS engine.

You, James Smith (served in SWAT for a decade with no failed ops), on vacation and driving your car to some nice place, to take a break from your usual work routines. Driving on a deserted road somewhere in Utah, the car breaks down. With miles of nothing behind, J. decides to go forward and stumble...