Media Molecule has already begun crafting a sequel to its long-awaited PlayStation 3 platformer LittleBigPlanet, which makes its official retail debut in the US this week.

Speaking with BBC News, the studio confirmed that a sequel is in development for the game, which allows players to make their own levels and share them online.

Beyond the sequel, Media Molecule and publisher Sony are investigating various spin-offs, such as LittleBigPlanet-branded comics, cartoons, and action figures.

In addition, technical director Alex Evans noted that some of the user-created levels seen in the recent beta--all of which will be available for download when the servers switch on--were better and harder than some of those made internally by the team.

Prior to working with Sony on the physics-based platformer LittleBigPlanet (PS3), developer Media Molecule has revealed that it was working on a game described "more Portally than Portal" and "Portal, but with scale factor."

The company even met with Valve, which suggested the two work on the game together.

"We were very tempted," studio co-founder Alex Evans told Kikizo. "But in the end we decided to talk to Sony and they just got the game at the beginning."

Media Molecule had previously worked with Valve for the Steam release of its physics-driven action game Rag Doll Kung Fu.

Developed internally at Valve, Portal (PC, PS3, 360) and its wit-driven take on puzzle-action shooting was released last fall to critical acclaim. It was inspired by the 2005 independent game Narbacular Drop, the creators of which are now at Valve.

LittleBigPlanet, originally unveiled in early 2007 as part of Sony's Game Developers Conference presentation, is slated arrive on October 21 as a PS3 exclusive.