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.

Gurra300 says

10/10 - Agree (2) Disagree

Best half-life 2 mod out there with a great story, great voice actors and a incredibly awesome gameplay, if this ever becomes an AAA title or standalone, i will buy this directly!