It seems to have strayed pretty far from the simple, focussed gameplay shown earlier this year.
What makes you say that? I think the problem here is the game spans three concepts - Create, Play and Share - and with different videos showing different elements people are getting lost (a bit like understanding what the PS3 is in general!). The gameplay hasn't been showcased as much as the creation aspects, but its still there.
So, the game is basically a 2.5D 'platformer' with the potential for physical puzzles. We don't know about 'hostiles' yet. The targets for a level are user defined. There was an earlier movie that was very good at explaining this but I'm blowed if I know where it hangs out! Anyway, you can set the player(s) to collect sponge or glow-stars or whatever, or set a time-limit, and stuff like that.
Then you have the creation element which allows you to customize your Sack Boy, and also build levels. This is a very simple interface but very versatile.
But finally, the wonderful twist to it all, it's all integrated into the one system that allows you to explore and adapt in all sorts of ways, where the creation process actually becomes part of the problem solving gameplay. Players have a certain amount of creation potential - you can think of this like money to spend on buying blocks and motors - and items that they can add to a scene. By playing the levels, more 'money' is earned and items are unlocked, allowing you to build more complex levels and devices. You could then integrate your creations into other levels.
For example, if you look at the video patsu posted, they build a crazy boxer. Now imagine a level with an Evil Boxer in the way that you can't get past. You use your 'money' and items to build yourself a boxer to beat him out the way! Or you build a tank to knock him over. Or you build a bridge over him. Or a catapult to launch a friend over, and he pulls a lever that causes an existing battering ram to swing down and knock the Evil Boxer over. The game combines some of the aspects of The Incredible Machine with platforming and most uniquely, user-created problem solving that's not tied to one particular solution.
The basic platform run-and-collect-a-thon that people know and understand is there. If that's all you want, fine it's there. For those that appreciate the creation aspect, they can use that in their game solving or level building or general customization. Showcasing slapping on shells and seaweed isn't showcasing the gameplay, but the way the engine integrates creation
with the gameplay.