Underhell is a Source Engine game developed by the Underhell Team in collaboration with We Create Stuff. Underhell Chapter 1 requires ONLY Source SDK Base 2007 installed. No Source game is required.

Jonex. says

9/10 - Agree (3) Disagree

An ambitious mod, with only a few flaws. I cannot wait for the next chapters to come out. It does so much with so little :D