Valve released Lost Coast to Half-Life 2 players yesterday, and we immediately put the tech demo/free level on our machines to see what the future of Valve's Source graphics engine is. Though it features about 15 to 20 minutes of gameplay, the Lost Coast was designed primarily as a technology demo to show off the difference that high dynamic range lighting can make to existing games. HDR, as it's known as, is a feature found only on the most recent generations of video cards, and it's going to be one of the next big things for graphics, particularly because all the upcoming next-generation consoles will support HDR lighting.

　　What is HDR? Find out in the Lost Coast...if you have a high-end video card.

　　So what is HDR lighting? Basically, it is a way of making more realistic light in a game, and the difference can be startling. You can download and play Lost Coast if you don't have an HDR-capable video card, though you won't be able to run with HDR enabled. If you do have HDR lighting, though, you can turn it on and see the difference immediately. It's definitely noticeable, and it's a big step up from the current lighting technologies. Basically, light looks more real, and brighter light sources have an almost blinding effect. Unfortunately, HDR lighting in conjunction with antialiasing and anisotropic filtering can take a lot of computing power, so you'll need a powerful card to really appreciate Lost Coast with all the graphical eye candy maxed out without a frame rate hit.

　　The actual gameplay in Lost Coast is fairly brief. It's technically a "stand-alone" episode in the Half-Life 2 saga. You wake up on a rocky beach, and an old man nearby tells you that the Combine have built a huge gun atop the seaside cliff that's shelling the town nearby. He unlocks a gate for you, and you must battle your way up the stairs and the cliff to get to the monastery that houses the gun. There's a fair amount of battling as you encounter various Combine infantry, but you still have your weapons at your disposal, including the crossbow, the shotgun, the submachine gun, and your trusty crowbar. Once you spike the gun, you must destroy a Combine helicopter using rockets, and then figure out a way back down.

　　The gameplay is thin, and the entire level is over in about 15 minutes.

　　Though it only has about 15 minutes' worth of gameplay, the Lost Coast is a cool taste of what's to come our way. For example, Aftermath, the upcoming Half-Life 2 expansion, will fully support HDR lighting. Meanwhile, Half-Life fans can enjoy the audio commentary that can be enabled in Lost Coast. There are 12 short audio segments that you can listen to that explain HDR lighting and the challenges of implementing it, as well as describing the benefits of it.

　　Lost Coast is now available for free to Half-Life 2 players on Steam, Valve's proprietary online distribution system. If you already own Half-Life 2, you can download it immediately, and if you purchase Half-Life 2, you can get access to it as well.