Microsoft has shown off 40 minutes of Project Spark in action on Twitch.tv, and we've got the video below for you to peruse at your leisure.
The team offered up a look at the game's level design and NPC AI tools.
The game is expected as a free download alongside the Xbox One's launch later in the year. The version displayed here is a Windows 8 build (with an Xbox pad) however. A 360 version is also in the pipeline.