It's a hard game to score. On the one hand, what it's doing is incredible and puts it head and shoulders above all the other titles out there. On the other hand, it is buggy and awkward. Even if they fix the disappearing geometry when collisions get too much, the jump mechanic with the automatic z-depth shift creates all sorts of problems. eg. The Metal Gear Shadow Moses level. The left to get the card has a central plank moving up and down, and ledges front and back of this. I got stuck on the front ledge. I couldn't just jump down onto the lift. I had to time it right to jump so the auto-position would place me on the plank, and it took an age! And then on the top, I had the same trouble. So I probably spent some five minutes on the same bit of screen jumping and getting nowhere. These issues can probably be addressed during design, but if you measure the game by what people are playing, and what gets published, then they'll plague the game. The actual jumping seems a bit unresponive at times too, which doesn't help.
As their prelude to the review quoted for SEUCK, LBP probably defies conventional rating. It's different things to different people. For many people the creation is fabulous. For others, thinking the widest possible audience, it's too complicated. I can't see many 8 year olds creating something that matches their vision. I expect a lot will get frustrated with the way edits affect stuff already created and give up trying. The game is incredibly beautiful, incredibly fun and happy, but also frustrating and awkward. For someone looking for the ultimate platformer, LBP isn't a 10.
Of course, every game has faults, and in that respect, going by the gaming press's standards instead of my standards, LBP should be a 10. It combines innovation and a whole new world of game dynamic, slapping an overpowered and unstable rocket-booster onto Gaming's behind and jetting it forwards.