There should be a harder version for this. idk how your going to do it but maybe just spawn some mini bosses in some of the boss rooms. Like for the easier ones, spawn some normal mini bosses, and for the harder, do super ones. and at the last boss, make a trap door to the final floor. just that room, 4 items, no doors just the big gold one. and have it so you already have the 2 key pieces.