As you play Dark Cloud you will find that the game records the number of times you have gone into the dungeon. A fun little challenge is to see if you can complete the game by going into the dungeon the least amount of times possible which is 17 times (this includes the final dungeon). The trick here is to go prepared and only exit when you reach a part of the dungeon which is impassible due to an event that needs to happen in the town or a character you need to get.
I have outlined the necessary dungeon trips below along with the mandatory reasons you must leave:
You can make it all the way down to the 8th floor where you have to fight Seda for the first time to get the changing potion for Xiao – you must get her to jump over the river to get to floor 9.
You can make it all the way to the bottom of the beast cave (floor 15) but you must leave to get the key to open up the room to Dran’s lair.
You can complete the divine beast cave.
You can get all the way down to Territory 9 and fight the werewolves. You must leave here because to need both the serpent sword from Trent and also the odd tone flute to summon the snake.
You have to go back to resolve Territory 9. In this trip you can summon the snake with the odd tone flute and kill it with the serpent sword. You get the necklace for Goro here but must leave again because only he can open the gate to the next territory.
With Goro in your party you can get all the way to the bottom of the Wise Owl Forest ( Territory 17 ). Here you must leave to finish the events in Matataki to get the Moon Grass Seed.
Here you can complete the Wise Owl Forest with the Grass Seed and Sun Dew to fight the boss Master Utan.
You can make it all the way to Layer 9 on your first trip into the dungeon where you must turn back because you need Ruby to get past the Crystal door.
You can make it all the way to the last layer ( Layer 17) but you need to leave to get the music box key to get to the boss.
During this run you will have all you need to get to the boss, La Saia, on layer 17 and complete the dungeon.
On your first trip into the dungeon you can get as far as Level 9 but will find you need Ungaga to get any further.
With Ungaga in your party, you can get all the way to the boss level 17, but need both the sun and moon signets to go further.
With the two signets you will be able to gain access to the King’s Curse and complete the dungeon.
In the initial trip into the moon sea you can get all the way to Crater No 8 where you find Osmond. He automatically takes you back to the Moon factory.
During this trip you can make it to the final floor (Crater No 15) but need to turn back to get a ticket to get into the coliseum.
With some event unfolding you get the ticket to the coliseum. Now you can get to the boss, Minotaur Joe, and complete the dungeon.
(final trip) : You can complete the entire 24 floor Gallery of time in a single trip and also fight the dark genie to complete the game. Since you can watch Seda’s memory fragment on the fly, you do not need to leave the dungeon for any reason.
This was pretty difficult to prove so I did the following: