Yeah, I'll try to get one of my friends to wifi it tomorrow at work. See how that plays.
Its perfectly playable by yourself though. Kind of hectic at times, but fun. As I said, in two worlds there was only one problem area, and another area where you needed to control both at once (but the face button controlling was just holding "up", easy)
Edit: Totally no idea what to do at the music boss, so I've gone onto the next world, a desert world. Much more coordination needed here. Often needing the microphone, stylus and face buttons. Luckily I discovered that the shoulder buttons work the same as the action button, which means you can use L to jump and hang onto things, and the stylus in your right hand (Or vice versa). Hope that helps anyone else trying to work out this game.
Edit2: Ok, turns out I just deleted my save by playing round in the other menu options. Man, I'm awesome. Anyway, got stuck in the desert world, maybe third level where the minigame was just a scene with sand, and the hint was to go horizontally over the sand with the stylus, but nothing seems to work. If anyone works it out (same with the music boss), please let me know.