Half-Life 2:  Lost Coast

Half-Life 2:  Lost Coast (Windows)  2005

First cube mapping (allow the reflection cast by an object to correspond with the brightness of the light source, and lightmaps enable light bouncing and global illumination to be taken into account in the rendering), first refraction effects (make light account for the physical attributes of an object and to emulate the way light is reflected by water), advaved HDR - High-dynamic-range rendering (final version of Valve's high-dynamic-range technology adds a significant number of lighting effects to the engine, aimed at making the game appear more realistic), advanced bloom shading (blurring bright edges in the game world and emulating a camera's overexposure to light. For example, as the player exits a dark area into a light area, the new area is initially glaringly bright, but quickly darkens (some elements of this technology used earlier in "Call of duty" (2003).

Gameplay video

Review - Computer Gaming World (CGW) (2006)
"Stiff-sounding show-and-tell wouldn’t matter much elsewhere, but this comes from the folks who made pheromones fearsome and robots our friends—and what they have to say is so interesting and insightful that cuing the next bobbing caption becomes incentive enough to stay tuned. And when full-of-ideas-but-never-full-of-himself director Gabe Newell offers his e-mail address and asks for our feedback, right away we know what to request: Give HL2 the treatment, too, please."

Trivia:
1) The Fisherman is the first Source character whose face was made from scratch without a real-life model.

2) First high-dynamic-range rendering was in Riven: The Sequel to Myst (1997).

3) This short free game is actually deleted level from Half-Life 2.