On the positive side, Monster High: Ghoul Spirit does do a pretty good job of capturing the Monster High world. You create a custom monster and pick its outfit from lots of options, and then walk around the school talking to all of the characters from the show. As a result, hardcore fans of the show might have a positive experience with the game.
Unfortunately, as a video game, this thing is just awful. This game is a clear case of the game makers phoning it in, knowing that people will still play it just because of the Monster High logo on the cover. The entire game is a plotless series of fetch quests where you walk around the same 10-20 room world over and over and over and over, doing the same cheesy wii-motion-based minigames and talking to the same people. There's no tension, no villain, nobody to fight, and nothing interesting to do. To top it off, the ending is a disappointing anticlimax.
Conclusion: This game might be enjoyed by someone who is obsessed with Monster High, but even in this case, they will probably be disappointed.