Also, the game bafflingly allows the team to commit suicide in co-op by accidentally pushing the A button to idle in a bubble.
This happened last night while my wife and I were playing. It's one of the few controller-throw-inducing-rage moments I have had with the game.
Single player, I'm loving most of the game, as much as I enjoyed the DS version at least. I searched around, found a warp cannon on my own, and am working through world 8 already. Mostly so I can unlock the "save anywhere" feature, which I also thought was a stupid unlock on the DS. Then I'll probably go back and get every coin, just as I did on the DS.
The new motion platforms and twisting mechanics are spectacularly done. It's a little bit of the old "rub your belly and pat your head" challenge, where I really have to focus on the right angle and timing my jumps. One castle, I think world 7, has you riding a crane-like platform, while bob-ombs rain down from both left and right. It was an intense challenge, and very rewarding when I finished it.
Overall a great game. But once again, the Wiimote seems to leave something to be desired. Seems like just another button or two (spinjump, maybe separate hold/run) would make the controls perfect. But I guess they did the best they could with what they have.