Multiplayer craziness totally refreshes old school Mario action.
Mario games were never super easy. They gave you timing, jump and puzzle challenges in just the right amount to make you feel like you accomplished something when you beat a level. Mario Wii is no different, and in my opinion is somewhat more of a challenge.
The biggest change to the series is having 1-4 characters playing the same level at once, not taking turns. Players jump on each other, get in each others way and cause overall chaos. It is great! When one player dies, they float back in via a bubble, and are at the mercy of other players to "unpop" them to get back in action. Also you can pick up other players and throw them.
Without giving away too much, this makes for great social gaming interaction, regardless of skill level. You design game plans, yell at each other, or even compete for the power ups.
The game itself is classic 8 world with 1 bonus world setup. Complete with shortcuts, ghost houses, power up games, castles, water worlds, lava, pipes, and kupas galore.
If you have friends who enjoyed the old school Mario and want to get in on some action, at the same time, this game will surely satisfy.