At Sony's GDC 2011 PlayStation lounge, Sucker Punch development director Chris Zimmerman revealed that inFamous 2 includes a full-featured set of tools for players to create their own missions in the game. After talking briefly about their plans to improve the game, he said that the biggest problem from the first game was that it ended. This is their solution.
Though technically not tagged with the "play, create, share" label, the influence and experience clearly show in the tools and incorporation of the user created levels into the game. I'm watching a level being created right now and the design tool allows the creation of just about anything an aspiring designer could want. It's all done in game, with a set of iconic tools for placing things like items, spawn points, triggers and so on. All manner of parameters can also be tweaked such as idle behavior, default response to Cole, and finer details such as response ranges.
From these tools it seems like there's no reason anyone, given the time and patience, couldn't create missions exactly like those in the game. Zimmerman actually said as much. Basic mission types from the game like defense, escort, search and destroy, and survival will be templates from which to start building.
But that's only a beginning point. The potentially more interesting creations are those that use the tool and environments to build something that wouldn't otherwise be in an inFamous game. Zimmerman said the Sucker Punch team gets most excited about these because user generated missions can go "off canon" as he put it. They're not limited by either story or established conventions of the game. Some of the examples shown are a shooting gallery, an old school platforming challenge, and a ring race.
Once created, missions go into the world right alongside the campaign missions. A ranking system comes into play to determine what you will see in your game. By default, Sucker Punch Featured Content will appear in your game. These are the levels that have been rated the highest, and played the most, by the community. You can also turn on filters, though, when there's a specific sort of game you feel like playing. So you might, for example set it to "newest puzzles" or "best shooters" for instance.
There's a lot to play with both as a designer and a player of the user generated missions. The full system will be in when the game launches this June and players will have access to most all of it from that time. There's not an unlock mechanic to getting the design tools, though some of the elements from later part of the game won't become available until you reach that point in the campaign. If you don't want to wait, though, a public beta is planned for this April, with signups starting March 14 on the game's official site.