I was once looking around the first Survival Games map in single player and I found this one puzzle near the borders of the map that required a record for a "sword of magic." To obtain a record, the player must use a skeleton to shoot a creeper, and those are the mobs. For this puzzle, even though he says mobs are optional, Vareide probably intended for the second map to have mobs when he made this. Even though this puzzle is already solved on this map, it would need mobs, so the whole map needs mobs. Please keep hostile mobs.