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.
Arguably one of the best mods I have played! Possibly the best! It has its issues and a few bugs here and there, but I expect that those will be worked out in future updates and patches. Biggest issue is that sometimes stuff isn't as straight forward as I would expect (but this isn't often) and sometime the cutscenes are clunky. The voice acting is hit and miss, but for the most part its average.
However, the gameplay and customized graphics (like new skins and such) are amazing! It was so much fun to play! It was intense at time and by the time I finished the prologue I was getting creeped out. It sets a great atmosphere and leaves me wanting the next installment to come quickly! Can't wait!
Overall, a well deserved 10/10 so far!