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.
After 3 months of being quiet, here is the first Gameplay Video of Underhell Chapter One, showcasing the sneaky and infiltration gameplay aspect of the game.
1 : None of the AI behavior is scripted
2 : The Dynamic Music is entirely in game until the final montage.
3 : It is still a work in progress.