Gears of War, a series known for its exclusivity to Xbox consoles, was once in development for a Sony system. A prototype build of Gears of War 3 for the PlayStation 3 has been uploaded by its owner to the internet, preserving the unreleased game. PixelButts, the one behind the "leak" described the beta as a demo build that Epic Games was working on in order to test how the engine ran on the PS3. The build was created exactly 10 years ago, in May 2011, but remained unusable and unplayable until last year. According to the Archive.org post, the game will not run on anything except specifically devkit PS3s, as they have extra RAM that helps the game to run. Currently, PS3 emulator RPCS3 does boot the game, but cannot get past the title screen. While the public release of the prototype is new, gameplay footage has previously been documented running on a devkit, and can been seen in the video linked above.
This is an archive of the original data built by Epic Games on May 19 2011 for Gears of War 3 for PS3 systems. Originally created during an engine test, and leaked 10 years ago and remained unusable data while circulating between collectors and exchanging hands. I was the first person to get this data working 9 years later, and decided now that it's time to release it on the 10th anniversary of this build being made (May 19 2021). To date, this is the only Epic-made data for a PS3 version of the game, as all others have been made with leaked source code.