A shame, then, that
The Grinch is simply not fun. While the adults in the crowd may appreciate a few of the challenges, the targeted audience of the game will give up in frustration before they get far into the game. Even the adults will get quite annoyed at the game and its lack of consistency or fun.
The basic conceit of the game is that you're out to ruin Christmas for the Whos, but you've lost all of your blueprints for suitably devious devices. So you've got to explore various parts of the Who world, completing missions and collecting parts of blueprints so that you can make the devices. The missions consist of causing various forms of havoc -- smashing presents, breathing on trees to make them wilt, and just making a nuisance of yourself. Of course, that's a good thing, because you're the Grinch.
The problem doesn't lie in the format of the game, but in the execution. You're given a series of quests for each world, but each quest is disturbingly similar. You'll have to smash n presents, or shoot eggs into m houses, or wilt z trees. And, as is disturbingly familiar in any sort of 'gratuitious fetch quest' game, you're often going to have problems finding that last item.
It doesn't help that you have to backtrack back and forth constantly to be able to complete any of the goals. This is normally a good thing in a game -- nonlinearity keeps it fresh. But in The Grinch, the amount of level-shuffling that you do gets to be downright annoying. And blueprint parts are often hidden in corners and other devious places, forcing you to search each level multiple times to make sure you didn't miss that one piece.
Some of the gadgets you get are cool -- launching eggs into houses is always amusing, and 'flight' is neat as well. But I'm not sure that anyone will be willing to deal with the game long enough to get to those items.