You can play this w/ the Wii-mote turned sideways ala the original NES controller. You have to shake the Wii-mote for certain special actions, but it's still the basic speed-boost and jump for the 1 & 2 buttons. This is my favorite!
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You can use the Wii-mote + nunchuck, and use the joystick to move around and the A & B buttons on the Wii-mote for speed and jump. I tried this, but kept getting the A & B buttons mixed up since it's not the usual system of using my thumb for both buttons like on the original NES and SNES games.
You cannot use the classic controller or a gamecube controller b/c the Wii-mote sensors are integral to certain actions in the game. You can tilt certain platforms and cannons by tilting the Wii-mote, and you can do certain tricks and attacks by shacking the Wii-mote.
I've been having a lot of fun w/ this game. I just got to World 7 last night. I've found a few secret cannons, so technically I'm on World 8, but I've been going back and beating every level possible, and trying to get as much of the coins and powerups along the way.
You can go to the Princess castle and spend your Star Coins to see some hints as to where the secret goals are, you can also watch some amazing footage of 'perfect' runs that are pretty cool, and you can learn how and where to earn infinite lives if you're into that.
Playing multiplayer is a great addition. I wish they had more of a battle mode (I haven't tried the coin battle thing yet, though). I was thinking of doing a house-rules kind of thing where you create 2 teams. Mario & Luigi vs the Toads. Mario & Luigi try to reach the goal before losing all their lives, and the Toads try to kill them. Then do vice-versa.
In multi-player co-op if you don't work together and take turns it turns into an unintentional kill fest! Oh, and if you're the last guy left (or everyone else is in a bubble) and you press A to go inside the bubble you all lose and have to start the level over.
I love bouncing on the heads of my co-players, and it's also cool that you can pick your co-players up, and throw them. You can also swallow them w/ your Yoshi and spit them back out.