Last May, leaked footage of Gears of War 3 running on a PlayStation 3 devkit appeared online. At the time, Epic Games noted how it had been used in Unreal Engine 3 for internal testing purposes and was never an "actual product work".
Now, the same prototype version (dated 19th May 2011) has been uploaded to the internet. The catch is, you're going to need a debug version of the PlayStation 3 to play it. The leaker apparently decided to release this build in celebration of the PS3 version's unofficial 10th anniversary.
As previously noted, the build in the video above is almost playable from start to finish, although some levels don't work properly due to scripting and checkpoint issues. It also attempts to read storage, as if it was running on an Xbox 360.
This latest online leak follows on from Rare's cancelled GoldenEye 007 remaster resurfacing online earlier this year.