This game is included with the purchase of Half-Life 2. It serves as a single-level tech demo, mainly to demonstrate High Dynamic Range (HDR) lighting, with commentary. Despite being a tech demo, it has a self-contained story of its own that is non-canon to the Half-Life series.
The Fisherman is the first Source character whose face was made from scratch without a real-life model.
The shell launcher, despite its printed warning sign stating that its moving parts can crush objects, can be disabled with any available physics object small enough to pick up and fit into it. Oddly enough, it cannot be destroyed with a grenade or any other weapon.
The town of St. Olga, where the game is set, was originally stated to take place between the levels Highway 17 and Sandtraps of Half-Life 2, but was dropped.