In the eight years since it launched, some may need a reminder that Left 4 Dead's original developer is Turtle Rock Studios. Well, that reminder has come this weekend with the release of an unfinished campaign for Left 4 Dead, free to anyone with a copy of it on PC.
The final mission is called Dam It, and Turtle Rock's Chris Ashton says it's a "gray box" work, meaning some features are incomplete "but it's playable from beginning to end." Dam It also packs in two standalone survival-mode maps that never shipped with the game.
Dam It is available as an add-on, downloadable here. Installation instructions are available on the page. There are a number of issues acknowledged in the add-on's notes, because it does not include any code changes that could resolve them.
There's also a very detailed map of the setting and the level design, which function as a nice strategy guide for those exploring Dam It. The campaign begins at an airstrip and wends its way through an apple orchard, into a deep ravine, through a covered bridge and a campground before the big finale at a hydroelectric power dam. It's set up so that players can split up to work independently, instead of cooperatively, to fend off the zombie onslaught and reach the conclusion.
Turtle Rock began work on Left 4 Dead in 2005, then was later acquired by Valve Corporation; after Left 4 Dead the studio was closed down and rights reverted to Valve, which published a sequel one year later. Turtle Rock Studios was reconstituted as an independent studio in 2010.
Turtle Rock was caught up in the bankruptcy and liquidation of THQ, for whom it was developing what ended up as Evolve, eventually bought and published by 2K Games. Support for that game was cut off at the end of October, though servers remain online for the foreseeable future.