Starts out strong, but once the wow-factor wears off Zack and Wiki becomes just a good game, but nothing too great.
Zack and Wiki is basically a point-and-click adventure. It uses the Wii Remote to point and to click, even for movement. By all means the game is innovative, but unfortunately that's all has to mask its just good main game. Eventually, you stop being wowed by how innovative it is, and just submit yourself to difficult puzzles that are worth completing, if only for the great rewarding feeling afterwards.
The game gets extremely difficult, and is a nice kick in the teeth for gamers looking for a challenge. It's a good thing the game is so difficult too because otherwise it would have been a bore. It's nicely cel-shaded and cute, but the plot is forgettable and to be honest, Zach isn't even that likable.
All in all, Zach and Wiki is a cautious purchase. Some people will never get bored of the control scheme, and those people will probably think the game is great. For other people, the awe will wear off and they'll be stuck playing a good game, but not one necessarily worth its $40 price tag.