Seeds of Doubt

The bucket and plant system is the core mechanic of Zetsubou No Shima — it underpins almost every preparation step and the main quest itself. Understanding it early saves a lot of time.

Getting a bucket: There is one bucket available in each of the four main areas: the Spawn room, Lab A, Lab B, and the main Bunker. Pick one up as early as possible.

Water sources (3 colours):

• Blue water — near Lab A
• Green water — near Lab B
• Purple water — underground in the Bunker, in the cocoon room

Fill the bucket at any source by interacting with it. The bucket holds 3 charges — you can water up to 3 seeds per fill, or water the same seed over multiple rounds.

Seeds: Zombies have a chance to drop seeds on death. Plant seeds in any of the growing spots around the map, then water them to grow plants. After obtaining the KT-4 or Masamune, shoot a seed after watering it to fertilize it for better results.

Plant outcomes by water colour:

• 3× Blue — Bonus plant: opens to give weapons, power-ups, or the Shell needed for the main quest
• 3× Green — Spike plant: impales and holds a zombie for several minutes (great for a safe break)
• 3× Purple — Carnivorous plant: attracts and kills zombies, but will also attack you
• 1× each colour (Blue + Green + Purple) — 25% chance of a Fruit plant (grants a free perk); otherwise a random plant
• Any 3 waters + KT-4 fertilization — Cloning plant: use it to save your current loadout; if you die you respawn with those weapons and perks

Tip: Spam seeds at every growing spot from round 1 onward and keep a bucket full at all times. The more plants you grow, the faster you will find the Shell required for the main quest.

Unlike other maps, Zetsubou No Shima has no single power lever. Power must be activated through a multi-step process involving water, an underwater section, and a timed door sequence.

Step 1 — Fill both generators:

• Pick up a bucket and fill it with any colour of water.
• Head to Lab A's generator and fill it. You now have a limited time to reach Lab B's generator and fill that one too. Move quickly.

Step 2 — Open the Bunker door:

• With both generators filled, a door in the main Bunker opens at no cost — head there immediately before the generators run dry. Be ready for infected zombies and a Swamp Monster.

Step 3 — Fix the underwater vent:

• Inside the Bunker, open the left door and go as far as possible until you reach a power lever. One vent is broken, so you must dive underwater.
• Clean the spider web on your left while submerged. The door will seal — kill all zombies that spawn until it reopens.

Step 4 — Flip the power switch:

• Once the door opens, go back outside — the power switch is directly in front of you. Interact with it to fully activate the facility.

Important: Make sure you have Juggernog or sufficient health before the underwater section. Spores on the cavern walls can restore your oxygen if you shoot them while submerged.

The Skull of Nan'Sapwe is the map's special weapon — left-click destroys zombies, right-click (Hypnosis) paralyses them. It is required for upgrading the KT-4 and the main quest.

Step 1 — Locate the skull altar court:

• From spawn, open the first two doors to reach a courtyard with a main altar and 4 pillars. There are 4 bloodied skulls here, each marked with a different number of arrows (2, 5, 3, and 6). Each skull must be matched to its corresponding altar elsewhere on the map. The altar symbols change each game, so inspect each altar to find the right match.

Altar locations:

• In the Spawn area
• Near the crashed gun-ship
• In the underground of the Bunker, near the KT-4 crafting table and sewer entrance
• Outside the Bunker, near the zipline and power lever

Step 2 — Complete 4 skull rituals:

• Place a skull on its matching altar. Green zombies will spawn and rush toward the skull — they will not attack you, but you must prevent them from destroying it. Defend it until the ritual ends, then pick up the white cleaned skull and return it to the main altar.
• Each subsequent ritual is harder: the 2nd spawns spiders, the 3rd adds a Swamp Monster.
• If a skull is destroyed, wait one round — it will respawn on the main altar.

Step 3 — Claim the skull:

• Once all 4 cleaned skulls are back on the main altar, a cave will open below. Enter and interact with the skull. You will be locked underground and must kill waves of Keepers. After enough kills, you will be able to pick up the Skull of Nan'Sapwe.

The Pack-a-Punch is submerged and must be freed by collecting 3 parts and interacting with control panels around its enclosure.

Part 1 — Fan cleanup drop:

• In the underwater section near the power lever (the same area from the power activation step), clean the spider web from the fan and allow the zombies to be pulled through it. A part will drop underwater — pick it up. This can be done before power is activated.

Part 2 — Cocoon drop:

• Head to the underground purple water room in the Bunker. Knife the cocoons hanging on the walls — they will release zombies and also randomly drop the part. Keep knifing until it appears.

Part 3 — Valve in the underwater caverns:

• In the submerged cavern network accessible from the Bunker (the same caverns where you find the flower for the KT-4), search for a valve. It will not be in the blue tunnel. Pick it up.

Unlock the PaP:

• With all 3 parts collected, return to the Pack-a-Punch. Find the three command panels around its fence and interact with each one. The water will drain and the Pack-a-Punch will become accessible.

The KT-4 is the Wonder Weapon of Zetsubou No Shima. It fires toxic projectiles and is essential for fertilizing plants and upgrading. It requires 3 parts.

Part 1 — Spider Venom (Lab A cage):

• After activating the power, go to Lab A and interact with the control panel to lower the cage.
• Wait for a spider to wander near it — she will enter on her own and the cage will lock. Head back upstairs and use the panel again to process the spider.
• Wait for the spider to explode and pick up the purple venom it leaves.
• Tip: Set this up before the first spider round (around round 6 when a fog rolls in and only spiders spawn). You can complete this step during that round.

Part 2 — Green Glowing Flask (Lab B zombie drop):

• After activating power, play in the Lab B area. Eventually a zombie will spawn with a green glow around it. Kill it and pick up the flask it drops.

Part 3 — Flower (underwater caverns):

• Inside the Bunker, open the front door and go all the way to the end. Go downstairs and open the door in front of Mule Kick. Explore the underwater cavern network until you find a blue tunnel leading deeper down. At the bottom is a glowing flower — pick it up.
• Important: Have Juggernog equipped or you will drown. Shoot orange spores on the walls to restore oxygen.

Craft the KT-4:

• Exit the water into the slightly flooded room near one of the skull ritual altars. Find the special KT-4 crafting table and craft the weapon using all three parts.

Near the main skull altar courtyard are 4 pillars, each showing 3 glowing symbols representing 3 personal challenges for that player. Yellow symbols are yours; blue symbols belong to other players. Challenges change each game but always have one Easy, one Medium, and one Hard.

Why this matters:

• Completing all challenges causes lightning to periodically strike the area around the altar, which electrifies your shield when equipped — a requirement for the Masamune upgrade step and the second gear in the main quest.
• Rewards: Easy = Max Ammo, Medium = SVG Sniper / Brecci Shotgun, Hard = Extra Perk Slot.

Possible challenges (examples):

• Easy: Use a spore to breathe underwater, Destroy 5 spores, Destroy 5 webs, Water 5 plants, Water a plant 3 times
• Medium: Kill 20 zombies underwater, Kill 15 zombies attracted by plants, Headshot 10 spore-infected zombies, Obtain a power-up from a plant, Kill 20 zombies using the fan trap
• Hard: Kill 8 spiders using a spore, Headshot 5 mutated zombies, Eat a fruit from a plant, Kill 30 zombies with the plane trap engine, Kill 3 zombies while they are mutating

Note: All players must complete ALL of their own challenges before the lightning will strike and shield electrification becomes possible. Coordinate with teammates to ensure everyone progresses simultaneously.

The Masamune is the upgraded Wonder Weapon and is required to complete the main easter egg. You need the Skull of Nan'Sapwe, the Shield, all trials completed, and 3 upgrade items.

Item 1 — Spider's Tooth (mini-boss fight):

• Head to the blue water source. Behind it is a large spider web — shoot it with the KT-4 to destroy it. You will drop into a cavern arena and the exit will seal.
• A giant spider boss attacks. Dodge her attacks and shoot her mouth when it glows yellow. She will summon spiderlings — focus on the boss. PaP'd weapons are strongly recommended.
• After killing her, a tunnel opens behind her. Pick up one of her teeth before leaving. On the way out you will pass a purple pool — stepping in it grants Widow's Wine for free.

Item 2 — Rainbow Flower (underground plant + skull steps):

• Head to the sewer entrance near the KT-4 crafting table and pay 500 points to be launched through the tunnel toward the green water. While travelling through the tunnel, you must press Interact near the 115 meteorite with an empty bucket to collect rainbow-coloured water. Spam the Interact button through the tunnel to be safe.
• Using the Skull's Hypnosis attack (right-click), interact with 3 torn posters/walls to restore their missing pieces: one near the purple water area, one at the left entrance of the Bunker, and one near the green specimen tanks.
• Go back to the underwater cavern where you found the flower. Use the skull on the wall facing the spore to reveal a hidden growing spot. Plant a seed and water it 3 times with the rainbow water (one charge per round) — the plant will hatch into a rainbow flower. Pick it up.

Item 3 — Element 115 Flask (electrified shield cage):

• Equip your shield and stand near the main skull altar. Once all players have completed their trials, the lightning will eventually strike and electrify your shield.
• With the electrified shield, run to Lab B and hit the console there. Enter the now-open cage.
• Solo: The cage will lower by itself. Multiplayer: Another player must activate the console while you are inside.
• At the bottom of the cage, press Interact to pick up the Element 115 Flask (your character will confirm it verbally).

Craft the Masamune:

• Return to the same room where you crafted the KT-4. There is a second crafting table nearby — use it to upgrade the KT-4 into the Masamune.

This is the first main easter egg step. You need to grow blue plants fertilized with the KT-4/Masamune until one produces a Shell, then use it to shoot down a large plane.

Step 1 — Grow fertilized blue plants:

• Plant seeds in any growing spot, water each one 3 times with blue water, and shoot each seed with the Masamune/KT-4 after each watering. This fertilizes the seed (you will see green particles floating around it).
• A fertilized blue plant will produce either a Bonus plant or a Cloning plant. You need the Bonus plant, which can contain a Shell among other items (Ray Gun, Monkey Bomb, Max Ammo, etc.).
• Tip: Spam seeds at every available growing spot and fertilize them all. The more plants growing simultaneously, the faster you will find the Shell. This should be started as early as possible in the game.

Step 2 — Load and fire the AA cannon:

• Once you have the Shell, head to the roof of the Bunker (accessed through the first door on the right when entering the Bunker). Approach the AA cannon and place the shell by pressing Interact where it would be loaded — you will hear a distinct clunk.
• Do not interact again immediately — the next press fires the cannon. Wait until the large plane is in the cannon's sights, then fire.

Step 3 — Collect Gear 1:

• The plane will crash and drop a smoking gear. Depending on when you fired, it will land near the green water area, in front of the Bunker, or near Lab A's zipline. Go and pick it up.

The second gear is located on an unreachable deck below the Lab A zipline. Reaching it requires an electrified shield and precise timing.

Prerequisites: All players must have completed their trials so the lightning strikes the altar area and can electrify your shield.

Solo method:

• Equip the shield and wait for lightning near the main altar to electrify it. Run to the Lab A zipline.
• Melee the zipline console with your electrified shield, then immediately use the zipline.
• While gliding above the deck below, press the melee attack button — this drops you straight down onto the deck. There is no inertia — you fall vertically like a weight, so do not press too early.
• Pick up Gear 2 from the deck.

Multiplayer method:

• Player A uses the zipline normally. Player B, with an electrified shield, waits at the zipline console.
• When Player A is directly above the deck, Player B hits the console with the electrified shield. Player A will drop straight down onto the deck.
• Critical: Player B must NOT press early — hit the console only when A is already above the deck, not before. Mistiming sends Player A into the water outside the map, instantly downing them.

Tip: Consider doing one dry run on the zipline to gauge the speed. Setting up a Cloning plant beforehand is highly recommended in case of failure.

The third gear is in a room completely inaccessible by normal means — above Lab A. The only way to reach it is by using the Anywhere But Here! Gobblegum.

Prerequisite: You must have the Anywhere But Here! Gobblegum equipped in your loadout before starting the game. This is a mandatory requirement and cannot be substituted.

• Activate the Gobblegum at any time during your preparations or after completing the other two gear steps. It will teleport you to the hidden room above Lab A.
• The third gear is on the floor near some large eggs. Pick it up.

Note: This Gobblegum can be used at any point during the run — there is no time restriction. Many players activate it early in the game to get Gear 3 out of the way while working on the other preparations.

With all three gears collected, it is time to commit to the final boss sequence. Once you begin this step, you cannot leave until the boss fight is over. Prepare fully before proceeding.

Recommended loadout before entering:

• Masamune (upgraded Wonder Weapon) with full ammo
• Pack-a-Punched secondary weapon
• Juggernog, Quick Revive (or Stamin-Up for mobility)
• Gas mask equipped
• Shield
• Afterlife / useful Gobblegums

Step 1 — Place the gears:

• Head to the elevator room to the left of the Bunker entrance (the path was revealed during the skull acquisition step). Place all three gears in the elevator mechanism.

Step 2 — Descend:

• Once all gears are placed and all players are inside, press the button. The elevator will descend.

Step 3 — Clear the roots:

• At the bottom, a corridor blocked by thick roots leads to the boss room. Shoot the roots with the Masamune to clear them. Pass through the final door.

The final boss is a monstrous wooden-swamp version of Ultimis Takeo, bound to the ground with 4 massive roots extending in 4 directions. Each root has a glowing spore on it.

How to damage the boss:

• The only way to damage the boss is to shoot each spore once with the Masamune. When hit, a spore will close — you must then survive and wait for it to reopen before you can hit it again.
• Each spore must be hit multiple times total. After enough successful hits, that root will be severed. All 4 roots must be cut to end the fight.

During the fight:

• Constant waves of zombies, Swamp Monsters (Trashers), and spiders will be thrown at you throughout.
• Max Ammo power-ups drop frequently — abuse your Masamune freely, especially charged shots for crowd control.
• The Gas Mask is essential here as spore gas will be present throughout the arena.
• Keep moving at all times and prioritise shooting open spores on the roots over killing enemies.

Once all 4 roots are severed, the boss lets out a final scream and the victory cutscene plays.

🎉 Congratulations — the Zetsubou No Shima main easter egg is complete! All players receive every perk on the map as a reward.