just hold the nunchuck down by your side then. theres no need to hold it up, all you need to do it use your thumb and fingers to move/duck/jump and what not.
just picked up the game today, the GF actually bought it for me cause I showed her the IGN video review and she wanted to get it played for a few hours and I'm on level 8. you sure theres only 12 levels? game is damn fun though, but I dunno how long it'll be until it just gets old.