In the early series, there seems to have been a definitive, specific, laid out path. An item was used in a particular location and if you didn't have the item (for whatever reason) when it was needed then you died. The problem is that this lead to the situation where you can do badly in the clue room and still get through the dungeon by being lucky with your selection of items. On the other hand, if you did well, picked up exactly the right items, but missed a clue (or didn't understand the advice given) you were certainly dead. So bad teams could progress and good teams could fail, and it wasn't necessarily clear why. Later series seem to have eased up on this and there always seems to have been an alternative approach available for taking the wrong items (at least in level 1).