Batman: Arkham Knight's gameplay demo shown during Sony's E3 press conference was in fact running on a PC not PS4, despite PlayStation symbols being visible on-screen.
During an interview with GameSpot, RockSteady's brand marketing producer Dax Ginn confirmed that the footage shown during the conference was from a PC.
While watching the footage back, Ginn is asked what build it is, and replies "this is the PC build". He also confirms that the game is running on the Unreal 3 engine, the same engine used for the previous Arkham games.
Batman: Arkham Knight is due out next year on PS4, Xbox One and PC. The PS4 version of the game will receive exclusive Scarecrow nightmare missions.