Medusa's Lair has taken many casualties. The Shrine has foiled a couple temple runs too. Some kids just couldn't get the hang of the Holes either. I love the Holes of Python.... mainly because of the Blue Pearl.
I think we can't undermine the S2 King's Storeroom. Sometimes, so much time was wasted in there.... it seemed to be the room where the kids didn't know what to do, too. Also, getting the key on the third pot and then opening the door on the third pedestal was killer.