Half-Life 2: Lost Coast is now available for play for all Half-Life 2 owners.
Half-Life 2: Lost Coast, a single-player level custom-created to showcase High-Dynamic Range lighting (HDR) in the Source engine, is available now to all owners of HL2. As a technology showcase, Half-Life 2: Lost Coast's system requirements are very high. During installation, Steam will prompt you if your system does not meet the recommended configuration. We hope you enjoy it.
- Source [2]