These games were developed by Yuke's and published by THQ. The .PS2 extension is not an official Sony format but is sometimes used by emulators or backup tools (like CD/DVD ripping software) to denote a raw PlayStation 2 disc image.

But recently, a much drier, more technical phrase has been popping up in retro gaming circles: .

The .ps2 extension denotes a memory card container that acts like a physical PlayStation 2 memory card. : Typically mimics a standard 8MB card.