The Sunken City is loosely based off of the Lovecraftian city of R'yleh, and reflects that in its appearance. It is a "reverse" world, where the player starts at the bottom of each level, and makes it to the level exit found at the top. The gravity of water is also flipped here, as it will fall upwards.
Many of the enemies here are seemingly much less dangerous than what the player previously encountered, as most of them simply approach the player and deal only 1 HP. The real hazard that Sunken City enemies pose is the large amount of time that the player is faltered after being hit by them, which could lead them to their doom into Spikes or Regenerating Blocks.
As an entirely separate location from the game not taking place on the moon, the Sunken City has seemingly built its own cohesive and strange ecosystem built between Frogs, Giant Flies, and their offspring.
Giant Flies (presumably) lay large egg sacs containing considerable amounts of Grub, which are eaten by Frogs and Fire Frogs, who are conversely eaten by Giant Flies, which are easily devoured whole by Goliath Frogs.
As Goliath Frogs are the "apex predator" of the Sunken City, Frog Traps were presumably constructed to cull their numbers.
7-1: Eggplant World Door, Waddler
7-1 always has the Mother Statue, next to the door to Eggplant World. Placing the Eggplant Child in the Mother Statue's arms will open the door to Eggplant World. It is possible to get 4 hearts by being in her arms for 10 seconds.
The final stop where the player can find Waddler is also found in 7-1. This time, it is simply out in the open along the main path instead of being a hidden door behind a wall.
7-1, 7-2, 7-3: Sun Challenge, Goliath Frogs
Upon entering the building with the Sun Challenge, Tun will say, "A warning, Reborn... the Sun Challenge may cost you your life." This warning is not to be underestimated or taken lightly by the player, as the Sun Challenge asks of the player to survive a massive swarm of Sorceresses, Vampires, Necromancers, and even Witch Doctors as they flood into the area via enemy spawners.
Tips and Tricks
- A common strategy to survive the Sun Challenge is to run up to one of the upper corners of the area, use a bomb to destroy the spawner up in the corner, and standing in a place where the nearby Frog Traps, Regenerating Blocks, or enemies cannot harm them until the challenge is complete.
- If the Sun Challenge spawns in 7-1, the player can use Waddler to bring Excalibur with them (along with Hou Yi's Bow if they plan to reach the Cosmic Ocean) into the challenge. As the blade will instantly gib enemies, Necromancers will not be able to resurrect them in response to their death. However, if the Sun Challenge does not spawn on 7-1, they cannot use it in the challenge without leaving Hou Yi's Bow behind with Waddler or using a second pair of hands to carry both it and Excalibur to the level containing the challenge.
- If the challenge spawns on 7-1, the player should hurry through the level to complete other tasks, such as navigating through the level, disarming Arrow Traps, finding Waddler or opening the door to Eggplant World, as it will not give the player a Four Leaf Clover and thus leave them with little time to complete these tasks safely before The Ghost arrives.
- The Clone Gun may be brought to the Sunken City, possibly with the help of Waddler or Hired Hands, and can be used to clone the Corpse Bag that drops after completing the Sun Challenge to gain a maximum of 99 bombs and 99 rope.
In 7-1 through 7-3, the playable character Dirk Yamaoka can be found within the guts of a Goliath Frog, who only spawn on these levels. Attempting to enter a Goliath Frog while it is still alive will cause it to eat the player, killing them instantly. Instead, a player must kill the frog first, where only then will they be able to enter the insides of the beast and free Dirk Yamaoka from his coffin. Tadpoles will occasionally be found floundering about within Goliath Frog bellies as well.
This level is always Hundun's Hideaway. Here, the player will ascend up the standard world generation of the previous three levels, with a major adjustment; Hundun will be pressuring the player upward into the main arena along with a spike pit, where the final major battle between the player and Hundun can begin.
Defeating Hundun will open a door at the top of the level that will allow a player to get the Hard Ending, while shooting the opened eye of a defeated Hundun with Hou Yi's Bow armed with the Arrow Of Light will open a portal to the Cosmic Ocean.
Reaching the Sunken City
The easiest, most sensible way to reach the Sunken City is by using the Qilin to fly up the Laser Trap section above Tiamat's Throne. To obtain the Qilin, one must obtain the correct Ushabti, which is located with the Tablet of Destiny, which is obtained after jumping through various hoops throughout the game.
Below is a step by step guide on how to make it to the Sunken City. This is when a player rigorously follows the questline.
Some of these steps can be skipped, such as skipping the Udjat Eye and finding the Black Market without it's help to get the Hedjet, or even retaining the Ankh while still going to Abzu. These are elaborated in the Skips wiki page.
For more information on specific steps, please refer to the articles written about the items/areas in question.
Step 1: Earn the Udjat Eye
Option 1; Collecting the Crown:
The Crown is found in Vlad's Castle, residing in Volcana. Placing the Udjat Eye in a socket in a Neo Babylonian structure at the top of one of the levels will cause a drill to bore it's way to the castle entrance. The Crown rests on a statue at the top of the castle, where Vlad resides.
Option 2; Finding the Hedjet:
The Hedjet is picked up in the Black Market, hidden behind the walls of The Jungle. When a player gets near the hidden entrance, the Udjat Eye on the HUD will begin opening and flashing blue. The closer a player is to the entrance, the more often the eye will flash. Once a player has deduced the location of the Black Market, they may bomb the entrance open. Within, they can purchase the Hedjet from a specific shopkeeper for $40,000, or even steal it if the player is willing to take the risk of almost certain death to the shopkeepers.
Tips and Tricks:
- Neither Vlad's Castle or the Black Market can spawn on either 2-1 or in the same level as the Moon Challenge.
- It is highly recommended to take advantage of the resources in either hidden area, such as Vlad's Cape, or anything that might be sold by Shopkeepers, such as Jetpacks or Bomb Boxes.
Step 3: Acquire the Ankh
The Ankh is obtained in the sub area of Olmec's Lair. In order to access the sub area, one must defeat Olmec by making him drop into the lava lake at the bottom of the level. As he sinks into the lava, the player will be able to enter the door to the sub area by standing on his head and waiting until it aligns with the doorway. From there, if they ascend to the top of the sub area, the Ankh will be waiting for them.
Option 1; Accessing Abzu:
Abzu is entered through a hidden door inside of a massive lava lake in Tide Pool 4-3. The player should first leave Excalibur at the entrance of the level. This is a very important step.
After, they should locate a door to a sub area. Within the sub area, the player will be able to travel to the bottom of the level where they will find a one way door.
Once passing through, the player can find and trigger an idol trap that will cause the lava to fall. Once the lava kills the player, the Ankh will resurrect them and teleport them back to the level entrance, where they left Excalibur. With the lava lake out of the way, and Excalibur in hand, the player can make their way down to the bottom of the level near the normal level exit and search for the entrance to Abzu down below.
Option 2; Delving into the Duat:
The Duat is accessed by sacrificing oneself on the Altar in The City of Gold with the Ankh in their possession. To reach The City of Gold, the player will have to defeat Anubis in 4-1 and seize his Scepter. Afterward, they can find a golden door in 4-2. With the scepter, and either the Hedjet/Crown in their inventory, the door to The City of Gold will open.
Step 5: Defeat Kingu/Osiris for the Tablet of Destiny
Option 1; Defeating Kingu
Atop the depths of Abzu, the player can face Kingu. With Excalibur in hand, the player can use the sub area to ascend up Abzu to get on Kingu's shell. They can then repeatedly swing Excalibur until Kingu is dead, leaving behind the Tablet of Destiny. The player can now take the door to the Ice Caves.
Option 2; Overcoming Osiris
At the top of the Duat, a Spelunker will find the judger of souls, Osiris. A few seconds after his appearance, Anubis II will spawn to provide backup. If the player can manage to kill Osiris, he will explode into emeralds, drop the Tablet of Destiny, and leave behind a portal to the Ice Caves.
Step 6: Using the Tablet of Destiny to find the correct Ushabti
Within Neo Babylon 6-2, an entrance to a sub area will be available. Within it will be every single possible variation of Ushabti. By reading the journal entry of the Tablet of Destiny, the player can deduce which one of the many to take with them to the next level.
Step 7: Riding the Qilin above Tiamat's Throne
If one successfully makes it to Tiamat's Throne with the Qilin still alive and well, they may use it's infinite flight to ascend past the Forcefields and Spark Traps at the top of the arena. They do not have to defeat Tiamat in order to progress here.
If the Spelunker succeeds in their ascent, they will find Tun beside a door congratulating them for their progress. There will be a one tile door next to her that the player must progress through, meaning that they must leave the Qilin behind. Behind the door will be an Olmec-shaped spaceship which will at last take them to the Sunken City.
Although the Qilin is the easiest, safest way to ascend up to the Sunken City, it is not the only way. Every other way to ascend is known as a Qilin Skip, and is written about in detail on the Skips wiki page.