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.
It's has great gamplay but the ingame cutscene not the normal cutscenes are way too long so most of the time I just zone out or take off my headphones so I just get the important parts and forget everything else. I hope in the next episode the in-game cutscenes have been cut down.