Ever since I started playing this on the NES, I still haven't stopped.
Sorry about the overreaction. But this game is AWESOME! Your objective is to jump, stomp, warp, throw, swim, and uncover your way to Bowser's castle and save Princess Peach. Although it sounds simple on paper (or screen, as seen here), it was quite deep at the time of release. Whether you're swimming past Bloopers and Cheep Cheaps, jumping over a Piranah Plant, or getting killed by a Goomba, this game is downright fun (and even more so addictive). I don't know why more people play Wii Play, when this game is ten times deeper, holds more gameplay, and is actually FUN.
Anyways, if you somehow don't have this game, BUY IT NOW!!!
P.S.
The only qualm I have with this game is that it will sometimes get frustrating.