It's not bad, but it's a little short from what I've seen. I'm not really going to complain since it was only $30. But I did notice that even though the game is relatively short, you can take branching paths. One path we took basically ended the level in under 5 minutes, but if we had taken the longer route, it would have taken over 10 minutes to get to the end.
I still need to pick up the zapper since I think that will make the game a bit more entertaining, but I think the game was worth the $30 overall. I've played through the story mode once completely in about 45 minutes, but like I said, there is more than one path to take when navigating each level.