If Portal 2 were to include only the pre-made levels that Valve is including, I’d still be in line on launch day to pick it up. As an awesome bonus, though, the PC version will include a set of mod tools that will allow players to make their own levels, turning the game into a LittleBigPlanet-esque experience with nearly limitless content. Sadly, the console versions will not include the mod tools. That’s okay, though, because levels created on the PC will be playable by players of both consoles.
In an interview with NowGamer, Valve’s Chet Faliszek confirmed that "the content that comes out is agnostic, and so we will be seeing that on all platforms." It’s not yet certain exactly how this content will be delivered to consoles, though, and Xbox 360 and PS3 owners may receive the levels differently; Faliszek also stated that PS3 owners would get some content via Steam for PS3.
In a separate interview with VideoGamer, Faliszek revelaed that two separate ending sequences have been recorded; one for single-player, and one for multiplayer; "Both sets of credits [will feature something special], because we've got two credits." It will be tough for Portal 2’s ending to live up to the legacy of its predecessor, but with two separate endings, its doubling its chances.