So… after diligently watching the internets all week, I received a beta code from 1up a couple nights ago. Last night I put in a couple hours to check it out. One sentence impression: This game is going to be HUGE. It’s going to sell like hotcakes and move a lot of PS3s too.
Edit: To clarify, Sony is doing some kind of limited open beta to test the servers, so you can’t just download and play yet - you have to get a key from somewhere. I got mine from 1up.com by sending in the answer to a trivia question.
For those who aren’t familiar with the game, it’s basically a platformer built around the idea of working together with other players to get through the levels. Check out videos at gametrailers.com (sorry for no link - I’m at work and can’t surf around too much). On some levels you have to navigate obstacles, on others you have to get through it as fast as possible. Sometimes you have to solve puzzles to progress. And sometimes it takes more than one person (you can team up online). For example, I’ve seen a couple levels where the task was to rearrange some blocks in a particular order, and in order to get the blocks up and over each other me and another player had to work together. The gameplay is simple but extremely addicting. And the visuals are outstanding (check out the HD vids at gametrailers for evidence).
The other side of the game is level creation. All of the tools to create your own levels are included in the game. You can then share your creation online, and of course play levels designed by others. The building tools are amazing, and I’m already blown away by the creative levels that are out there. Last night I played one where the designed put rockets all around a large upright wooden disc (like a solid wooden tire) all pointing clockwise. When I grabbed the sponge in the center of the disc (that’s the typical “grabby” material), the rockets activated and rolled the contraption through the level, picking up speed as my sackboy hung on for dear life.
Another level, called “Little Big Colossus” (I think), had sackboy riding on his trusty black horse “Agro” (a shout out to Shadow of the Colossus, an old Playstation favorite). There are all kinds of levels out there already, and this is just the beta. There are even levels that are just there for the comedy, like the one where a character asks you to step on a switch to turn on his Xbox 360, only to have red rings rain down on him when you do. I played another that had me following Rick Astley around the level as he told me what he was never going to do. Old yes, but still entertaining.
There was also one where sackboy just rides a vehicle from one side of the level to the other, while tripping sound events along the way. As your going, the sounds combine to play a little song. Not much of a level (you just sit there), but very creative.
The biggest surprise for me is that already a lot of the user-submitted levels are easily on par with those included with the game. There are apparently a lot of creative people out there dying to get a hold of this game to see what they can do.
I’m just getting into the building aspect of the game, but already I’m daydreaming about what I can put together. You really can build just about anything you can imagine. I’ve seen all manner of rocket-powered skateboards, monsters, robots, etc.
I’ll write more when I have more time, but in summary: Put aside $60 people, this is a must have. And if you don’t have a PS3, put aside $460. It’s worth it, trust me. 
Anyone else in the beta? I’m SlackerCS on there if you want to hook up. 