glaringly bright, but quickly darkens, representing the adjustment of the player character's eyes to the light. New cube mapping techniques 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. Refraction effects were added to make light account for the physical attributes of an object and to emulate the way light is reflected by water. The Lost Coast level is specifically designed to showcase these effects. It uses the sea and beach as opportunities to demonstrate water-based effects, the monastery to demonstrate bloom from its whitewash walls, and the sanctuary to provide the means to show refraction through stained glass windows and cube maps on golden urns and candlesticks. As a technology showcase, Valve considered Lost Coast to have very demanding system requirements. The game runs on computers with specifications lower than what is recommended, albeit without some key features such as high dynamic range. If a non-high-dynamic-range-capable card is used, the developer commentary is changed slightly to reflect this. For example, Valve president Gabe Newell would describe the effects that are seen differently. Commentary system In addition to a showcase for visual improvements, Lost Coast acted as a testbed for Valve's commentary system. When the feature is enabled, additional items appear in the game that can be interacted with to play audio commentary. Each audio piece ranges from ten seconds to a minute of commentary. Players hear the developers talk about what the player is seeing, what is happening, why they made certain decisions, and what kinds of challenges they faced. Commentary tracks are represented by floating speech bubbles called commentary nodes. Valve intended for players to first play the level with commentary disabled, and after completing the level, play it again with commentary enabled, learning about each new stage as they progress. The company has since made the commentary system standard in all its later video games. Release and reception Lost Coast was released on October 27, 2005, as a free download from Valve's Steam content delivery service to anyone who purchased Half-Life 2. People who received Half-Life 2 as a gift from Valve's online store were not eligible to download the level. Valve announced on May 30, 2007, that Lost Coast, along with Half-Life 2: Deathmatch, would be made available for free to owners of