Included in the
Marvel Level Kit are three new music tracks for use in your levels - two normal background music pieces and one interactive piece. There is one new background of what looks to be New York rooftops and has a very nice three dimensionality to it, rather than simply having a couple of layers of parallax scrolling.
As for materials, there are six new materials to play with: three comic-book styled pen-and-ink backgrounds, one of a cityscape, one of a grid of windows (think close-up detail of a skyscraper) and one of repeating text balloons, two repeating comic book character montages which look a bit like either gift wrap or a child's wallpaper and an orange "Thing" texture. The Thing texture is a rock texture and has a rock hardness and rock sounds associated with it, while all of the other included materials are in the "Cardboard" category.
There are a lot of stickers included, with several Marvel characters having body stickers (arms, legs, chest and head). Additionally, there are some 3D modeled heads (such as Thing and Iron Man), which look fairly awesome. I used the Thing head in a level where he had been made into a rampaging giant, and built part of the level as the Thing's bust, with the provided head on top. It came out pretty cool, in a fairly hilarious sort of way that seems typical of LittleBigPlanet.