Something similar is also being done for the four-player competitive ad hoc mode -- essentially races through each level where players will be able to see the "ghosts" of their competitors, but not the way their level happens to be tilting, because that'd just be silly ... and vomit-inducing.
The most important addition to Midnight Carnival's gameplay is the "Boing," a new move performed by holding one or both shoulder buttons for a two-count and letting go. It causes the LocoRoco to rocket higher/farther than a normal jump, and is accompanied by a colorful trail that's left behind them. The idea is to maintain as long a string of Boings as possible through each stage; to that end, the levels are built so that, with enough skill, it's possible to launch from one Boing to the next, adjusting trajectory mid-air in order to collect all of the items.
Since it's played completely with the PSP's shoulder buttons, it's actually possible to play the game on the PSP Go with the system "closed," using L and R to navigate menus and make selections, as well.
The game will be available in October, and is unique among the digital-only releases being prepped with PSP Go in mind, in that the "demo" version will actually be the entire game download -- with only two levels unlocked. After completing them, players will be offered the option of buying and unlocking the full experience right then and there. So, basically, it's just like trial games on XBLA.
We asked Sony if this will be the norm with digital releases (it makes so much sense!) and were told that developers will have the option to do so. Currently, Midnight Carnival is the only title built this way.
Based on our play time with this (so far) very enjoyable sequel, the "buy now" option is going to be used quite frequently.