EDIT: Front-end is the same (including music, which is a shock when you haven't heard it for a while, haha). From what I can see, and I might be missing something obvious but I don't think I am, you can't change the camera angle in the demo (which is obviously to hide the slowdown, either because Konami are being deceitful or because they're working on a patch for it). Game speed is the same, slowdown on cut-scenes is the same. Crowd are still pixelated. There is an extra difficulty as ThomasGOAL has already reported, "Super Star", but I'm not noticing any difference between Top Player and Super Star - perhaps it's another Master League only thing, who knows. I'm sure it must do something but honestly, I can't see any difference.
Most dissapointingly, goalkeepers are still the same, and can't catch basic shots.
I don't think it's any different from PES2008, personally. I certainly haven't noticed anything different in the gameplay myself.