You go through a few phases, each getting harder than the one before. It is quite fun, but can also be really frustrating if you don't know exactly what to do. Beth had posted a really helpful strategy so I went with that right away and it worked out for me the second time around.
It was really fun, so go check it out! Well, with only 10 minutes until I can play cataclysm, I'm going to end with this :) More posts to come this week!