Boss Tricks: Spire
Easily defeat Spire and save time in Elder Chamber by doing a DBJ through the hole between floors. Do not defeat any of the enemies before doing so. Once on the second floor, destroy the enemy spawner and any enemies it may have summoned, triggering the appearance of Spire. He will appear right near you but will ignore you and jump down to the lower level, at which point you can fire away without taking any damage.