Source SDK mod Estranged: Act I now on Steam for free

It's always nice to see a mod progress from humble beginnings to its own Steam product page, and Estranged is fully deserving of the achievement. Alan Edwardes' spooky, puzzle-filled FPS plays and looks like a first-person Alan Wake , and it's an excellent deviation from standard run-and-gun zombie-fragging with its supernatural twists and an atmospheric sense of foreboding. The first act is available on Steam as a free download independent of any Source-based game, so you won't need Half-Life 2 to jump in and start exploring.

Washing ashore on a misty, moonlit island coastline, you'll need to both figure out what happened and how to escape from the island's strange and sometimes hostile inhabitants. The story, like most well-crafted horror yarns, shrouds itself with mystery and urges exploration to reveal the truth. It's a particularly effective strategy, as Edwardes and his team poured a wonderful degree of detail into the island's foggy docks, murky woodlands, and eerily empty houses.

And when the monsters—glowy-eyed zombie/infected hybrids—do jump out from the shadows, the game shines with a less-is-more approach of eschewing musical cues or zombie groans for more silent and sudden attacks. Running away is often just as correct as fighting, since you'll find yourself hoarding the precious bullets and medical supplies you'll scrounge up as long as possible. Trust me, after getting my back clawed to pieces by a zombie who I could've sworn wasn't behind me a second ago, I can assure that rush of adrenaline will be genuine.

Estranged has come a long way since its beta became the Mod of the Week last September, and seeing just the first act appear on Steam suggests more to come from Edwardes to further unravel more pieces of the island's riddle. Grab it for free on Steam , and check out the official website for more screenshots and info.