My friends and I were playing 4 player and we ran the Crypt of Horrors on normal just fine. Some of them couldn't complete the one quest, so we went through on Hard after that. At the end of the dungeon, one of my friends came out with the items he had when he went in, and didn't get any of the loot he picked up from the dungeon. The only thing he kept from the Hard level run was his level advancement. He didn't get the quest marker from it, either.