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.

higgie says

1/10 - Agree (1) Disagree (75)

It should be easy to play, but mission is very fussy about the methods... I am not happy about it it ended in mission failure.