Step 1
Activate Pack-A-Punch
Grab the Power Switch from the Beach and place it at the Power Station to turn on the power.
Pick up Elvira's Book from the safe in the Diner.
Give the Book to Elvira — she will give you a Blood Vial.
Pick up the Cleaver melee weapon from the dead shark in the Beachside Market.
Get kills using the Cleaver to fill the Blood Vial.
Give the filled Blood Vial to Elvira — she will follow you.
Bring her to the portal outside the TV Station and she will open it.
Enter the portal to be taken to Pack-A-Punch.
Note
After this, the Pack-A-Punch portal will respawn at various locations around the map. Look for a beam of light in the sky leading down to the portal to find its current location.
Step 2
Zombie Parts & Mirror Pieces
Head: Enter the Projector room and interact with the red button on the wall, then immediately leave the portal. You'll be taken inside an RV — grab the Zombie Head from the counter before you get kicked out.
Torso:
- Pick up the Crowbar in the Motel side room.
- Pick up the Freezer Trap part from the side of Ramon's Gas Station, on some boxes.
- Place the part on the missing slot of the Freezer Trap in the Beachside Market to repair it.
- Activate the trap, then melee the pig carcass in front of the Torso to remove it and pick up the Torso.
Left Arm: Pick up from the firepit in the RV Park.
Right Arm: Build the Seismic Wave Generator and place it on the green spot on the beach where the Power Switch was. This raises the Zombie Arm for you to grab.
Seismic Wave Generator — place each part one by one on the Build Table in the Diner backroom:
- Blueprint — Diner, outside the door leaving the back room
- Ring — Diner, outside on the corner near the Pack-A-Punch portal
- Stand — Diner, on one of the red benches out front
- Thumper — Playground, corner nearest the Diner next to a Portapotty
Left Leg: Pick up the Cleaver melee from the dead shark, then melee a Soldier Zombie (spawns round 5 and after) to make it drop its leg.
Right Leg: Throw an explosive into the tree in the Forest near the TV Station to dislodge the Zombie Leg.
Hand Mirror: Summon Elvira (after filling the Blood Vial with Cleaver kills), then pick up the Hand Mirror from her couch.
Glass Shard: Pick up the Crowbar in the Motel side room, melee the intact mirror in the RV Park bathroom, and pick up the Glass Shard.
Car Mirror: Pick up the Crowbar in the Motel side room, melee the right-side mirror off the car between the Beachside Market and the Gas Station, and pick it up.
Step 3
Contamination Tent Setup
Place the Zombie Parts on the gurney in the Contamination Tent.
Place the Glass Shard on the table next to the gurney.
Place the Car Mirror on the wooden crates.
Place the Hand Mirror on the MRE crates.
Step 4
Punch Card, Typewriter & Death Ray
Pick up the Punch Card from the table in the Diner backroom.
Place the Punch Card in the typewriter in the Contamination Tent and interact with it. Lights will flash left to right, representing numbers 0-9.
Randomly input the numbers 3, 4, 5, 6, 8 until you find the correct order by trial and error — 8 will always be last. Remember the correct order.
Once the correct code is entered, interact with the Death Ray next to the typewriter to shoot a laser into the Zombie Parts and turn it into a zombie.
Step 5-6
The Key
Input the same code, but backwards, into the typewriter, then activate the Death Ray again to turn the zombie into a Key.
Use the Key to open the garage of the Gas Station.
Step 7
Chemical Station & Nuclear Bomb Parts
Chemical Station parts — place on the table in the Garage:
- Beachside Market — on a couch in the back room
- Trailer Park — bench next to an open RV
- Beach — bench on the trail to the RV Park
Nuclear Bomb parts:
- TV Station — under a gate that leads from the Forest to the TV Station
- TV Station/Motel — under the crashed red car on the road between the TV Station and the Motel
- Beach — under the small bridge at the back of the beach with flowing water
Step 8
Gauge Code
Memorize the 4-digit code under the desk in the Beachside Market office.
Pick up the Crowbar in the Motel side room.
Melee 4 gauges around the map to stop each one's number on one of the 4 digits from under the desk (any order):
- Power Station — behind the building with the Power Switch
- Gas Station — behind the Gas Station
- Motel — inside the side room with the Crowbar
- Snack Shack — near Quickies on the right side of the Snack Shack
After all 4 gauges are set, the safe in the Beachside Market office will open and contain the Bomb Code.
Important
Memorize or note down the Bomb Code now — you'll need it much later in the boss fight and won't be able to check it again.
Step 9
"M" Number
Find and memorize your "M" number — it's found in the Motel Office on top of one of the walls.
Step 10
"O" Number
Find and memorize your "O" number by changing the color in the TV Station using the TV Equipment, then looking at the 4 "O" symbols at different parts of the map:
- Beachside Market — back room, above the fridge
- Gas Station — on the front door
- Beach — on the bottom of the big bridge
- Trailer Park — on the fridge inside the RV accessible from the Projector room button
For each of the 3 colors, one of the "O" symbols will be crossed out. Find which 3 symbols get crossed out across all 3 colors and disregard them — the one symbol that never gets crossed out is your "O" number.
Tip
For the Trailer Park "O" symbol, you don't need to actually use the Projector room button — just jump up and look through the window from outside.
Step 11
Eye Number
Multiply your "M" number and "O" number together to get your Eye number.
Look at the TV in the TV Station, next to Elvira, and find which color corresponds to your Eye number. Memorize this color.
Step 12-13
Battery & Radio Audio Logs
Obtain a Battery, randomly dropped by Backpack Zombies.
Place the Battery in one of two radios and listen to the audio logs for the scientist to name a chemical that can stop the Radioactive Thing. There are 5 possible chemicals he can name:
- Power Station — on the ground behind the building with the Power Switch
- Motel — office, on the couch
If the radio you used the Battery on instead gives lines about how to make chemicals (rather than naming the target chemical), use your other Battery on the other radio to find out which chemical you've actually been given.
Step 14
Mixing the Chemical
After determining your chemical from the audio log, select it below to see the full ingredient chain and where to find each ingredient:
Change the color on the TV/lab setup to the color from your Eye number step.
Place the first row of ingredients for your step on the Lab set in the garage.
Locate each ingredient's board, and note down the top and left number in its diamond. Add all these numbers together, then subtract your "O" number to get the final number for that combination.
Input that number into the display at the top right of the Lab to confirm. Done correctly, this creates the intermediate chemical. Repeat for each step until you have your final chemical.
Example
If your color was Red, set it to Red first. Suppose your final chemical is "3,4-di-nitroxy-methyl-propane": you'd get Quarters (melee the payphone with a crowbar) and Racing Fuel (outside the garage), and place both on the lab table. Checking the boards — say Quarters shows 5 & 3, and Racing Fuel shows 4 & 7 — that's 5+3+4+7 = 19. If your "O" number is 5, then 19 − 5 = 14. Enter 14 into the machine and confirm to create Formaldehyde. Repeat with the next combination (e.g. Pennies and Vodka) to create Acetaldehyde, and so on until you reach your final chemical.
Step 15
Arming the Nuke
Once you have your final chemical, place the Nuclear Bomb parts on the Nuke in the garage.
Place your final chemical on the Nuke.
Final Steps
Boss Fight: The Crogzilla
All players need to interact with the Nuke to start the charge-up sequence. After 30 seconds, the Nuke will be charged — all players must interact with it again to begin the boss fight.
Phase 1 — Escort:
- Escort the Nuke as it makes its way to the beach. The Crogzilla will shoot eggs at you during this.
- Once the Nuke reaches the beach, it will launch — and the Crogzilla will eat it.
Phase 2 — Lasers:
- Use one of three lasers (left, middle, or right of the beach) to shoot open a hole in the Crogzilla.
- When the Crogzilla charges a laser attack, a small glowing spot becomes vulnerable on its chest — shoot a laser at it during this window while avoiding its laser and slam attacks.
- Once hit successfully, the spot stays open — keep hitting it until the Crogzilla is stunned and the spot closes.
- The number of hits required is 2 × number of players + 1 (e.g. a 3-player game needs 7 hits).
Phase 3 — Final Sequence:
- All players interact with the hologram nuke on the beach where the original nuke was, then immediately run to the back of the beach.
- The Crogzilla will spit acid on the ground, locking onto more of the beach over time. You're safe at the very back of the beach by the signs.
- Once the acid reaches near the back, the Crogzilla sends two waves of eggs (only one wave on attempts after the first).
- The acid then disappears and a laser maze appears. All players must traverse it (left path recommended, right also possible) and reach the Nuke in time, interacting with it simultaneously.
- Done correctly, this teleports all players inside the Crogzilla with the Nuke.
- Each player must enter the Bomb Code from Step 8 into the Nuke, interacting and pressing the correct numbers left to right, to get a green light on their side.
Tip
If a player is struggling to enter their Bomb Code, another player can jump over the bomb to their side and enter it for them.
Completion
After all players successfully enter the Bomb Code, a cutscene plays and the Main Quest is complete. If playing in Director's Cut, you can also collect the Talisman.