SolidSnakex said:
At its heart it's still a 2.5D physics based platform game. But since you have creation tools you're able to create different types of games too. That should be expected.
I would disagree with your sentiment though. The fact that it's a 2.5D physics-based platforming type game is definitely an important and fixed factor, but it's not what is at the "heart" of LittleBigPlanet. I would think that the core of LBP is closer to something like an "engine" than it is a "game". The 50 levels and single-player stories that come along with it may be brilliant, but they are also in my opinion, accidental and not crucial.
Think of how Unreal Engine 3 is a game engine that allows you to more easily create your game. It is higher level code; away from the binary, away from the low-level C++ and you don't need to create an engine from scratch; instead you have a set of parameters that you work within to build a world using the tools of that engine. RPGs, fighting games, music games, shooting games -- all can be built with UE3.
LBP is something like an even higher-level game engine. There are a set of parameters that you can operate within; the creation tools and material they afford you, the adjustable qualities like physics, fog, and so on, the necessity of Sackboys as characters, and the fixed gameplay quality of 2.5D platforming. On top of this you can build anything you want within those parameters, tug of war games, puzzles, tributes, races, fighting games etc. The boundaries of creation are not as broad as a game engine like UE3 but usability of the user necessitates that. You sacrifice customizability for a more limited set of choices.
I think from the very beginning, LBP's focus was on customization and level creation. Phil Harrison was the one who pushed their concept further to the "Share" component, giving birth to what I think is going to be the core of LBP - the community.