Microsoft has shown off its answer to LittleBigPlanet with Project Spark, a new title for Xbox One and Windows 8.
The game enables players to create their own games from a massive library of preset objects and environments, which can be selected by voice commands using Kinect or with the controller.
A second player can take part using Xbox Smartglass on any device or Windows 8. This allows them to sculpt levels and environments in more detail, for example.
The demonstration by Microsoft Studios' Dave McCarthy during today's E3 press conference showed two players quickly creating a fantasy landscape, a battle between goblins and villages, and a rock that becomes a giant robot.
Completed games can be shared with other Xbox One users.