A useful feature for speeding up dungeon clears until flash is unlocked would be to open chests as they are found, to first reveal all the chest locations, then reveal the entire map to rush the boss. This would be greatly helpful when you've gotten your attack so much higher than what's needed for the dungeon that you oneshot everything in there anyway even with the health boost from the chests. Using this strategy makes dungeon clears much quicker for the first 200.
A useful feature for speeding up dungeon clears until flash is unlocked would be to open chests as they are found, to first reveal all the chest locations, then reveal the entire map to rush the boss. This would be greatly helpful when you've gotten your attack so much higher than what's needed for the dungeon that you oneshot everything in there anyway even with the health boost from the chests. Using this strategy makes dungeon clears much quicker for the first 200.