This video shows the location of every Key in order. If you want to use the original guide, or if you need help on a specific Key, it can be found below.
Mach Dash into the wall above the entrance to the Elevator room on Floor 1.
Talk to Snick in the SAGE Building, then the Key spawns in the block to the left of Oregano Mirage.
Super Jump up to the right facing wall to the left of Gnome Forest, then Shoulder Bash a little less than half way up the wall.
Super Jump slightly to the left of The Three-Cheese Tundra, then Shoulder Bash into the left wall when you’re almost at the top.
Super Jump past the one way platform to the right of You bring a light?, then Shoulder Bash right into the corner.
In the Floor 1 Secret room, shoot the gate with a pistol bullet (using the “Pistol Chainsaw” side attack, not Vigilante’s pistol).
While outside of the SAGE Building, input the Konami Code (↑ ↑ ↓ ↓ ← → ← → B A) using the arrow keys to become Mario. Now enter the building and press up on the Bloodsauce Dungeon machine to enter 1-1. Play through the level to find the Key where the top of the flag would normally be.
In the Floor 3 Secret room, grabbing and throwing the washing machine in the water 3 times will reveal a Key.
Talk to GPB until he mentions “the locale”. Then, visit the Granny Pizza in the Floor 4 Secret room and press up to talk to her as a normal NPC. After this, you can find the Key hidden in a crawlspace under the mushrooms on Floor 3.
First, talk to GPB. When he mentions “someone in the roof”, it starts a chain where you must first talk to Pepperman in the Floor 1 Secret room. After this, visit the Floor 5 Secret room and Super Jump in front of each of the 3 paintings, destroying them. After which, the Key is spawned in the center of the room.
Ground Pound directly in front of the Peppino statue by the entrance to reveal a Key in the floor.
In the Wrong Mod room, jumping into the ceiling reveals a hidden area with a Key and a Pizzaboy cutout.
In the long tunnel between Floor 5 and Top, you can find a Key hidden in a breakable wall on the left. Avoid using the present to get up.
At the very top of the tower, you can collect a Key by falling off the right side and hugging the tower wall.
Floating above the pedestal in the Green Room, right before you enter CToP. (Note: The Key may be behind the score text.)
Shoulder Bash left into the opposite corner of the Floor 1 Secret room.
Floating in the middle of the ring on the SAGE Building.
Wall Run into the ceiling slightly to the right of the metal block next to Crust Cove.
On Floor 4, there are 6 locations for the Key to spawn. It will randomly choose one of them. Watch the video to see them all.
Talk to GPB until he mentions "someone similar to you". Now, take the elevator to each floor in descending order and find Fake Peppino, who should spawn nearby. He only has a 50% chance of spawning on each floor. You can advance to the next floor if the save icon appears. Once you reach Floor 1, he will drop a Key. There is a rare softlock that can occur if you don’t pick up the key on Floor 1.
In the 4th room of CToP, “He Watches”, you can find a Key by rolling into the small room with the Tomato Toppin Animatronic.
In the 9th room of CToP, “Quickly, to Space!”, there’s a Key on the ground between the Banana Peel and the Antigrav Bubble with the three Golf Burgers.
On Floor 3 there is a secret to the right of the water just before the next room with a Key inside.
In the 12th room of CToP, “Not the Time for Games”, dodge the first cow (or abuse the character select taunt) after the Minigolf section to find a Key on the ground below.
On Floor 2 there are two John blocks in the ceiling above Oregano Mirage. Ground Pound directly below them during Pizza Time to collect a Key.
You can continue breaking blocks in the same place you found the 1st Key. Talk to the Pizzaboy Clone and Super Jump directly above him to collect the Key.
On Floor 2 there is a crevice in the floor between Wasteyard and Fast Food Saloon. Ground Pound on the right to reveal a new tunnel. Talk to the Pizzaboy Clone and run right on an invisible path. The Key is on another pillar in the void.
Wall Run to the left of Deep Dish 9 to access another room. You can go through the ceiling on the right side to talk to the Pizzaboy Clone. The Key will spawn in a secret in the left wall of the bottom room.
Super Jump from the right half of the Oh Shit! gate to find a secret room. Enter the door and talk to the Pizzaboy Clone. The Key will spawn on a platform below you.
Repeatedly enter the Void Room until a new platform spawns by the entrance (1/10 chance). The Key is on top of it.
In Pizzascape, the Key is in a new room above the Secret that’s only available during Pizza Time. If you can’t access it, talk to GPB in the Void Room and try again. Complete a short challenge to find the Key and a Pizzaboy Cutout.
In Wasteyard, the 3rd room (“The Pit”) has a new secret in the pillar to the right of the two Ranchers. This brings you to a maze with 12 places for the key to spawn, chosen at random. Watch the video for a path to check them all.
In Crust Cove, there is a pit to the right of Pillar John with a door in a secret in the right wall. Switch your Grab Type to Pummel to cross the water without activating Pizza Time. Complete the challenge to obtain the Key. Switching to Vigilante may help, as his dynamite can kill the Rats and prevent a softlock.
In room 12 of The Three-Cheese Tundra (“Back of the Fridge”), there is a platform at the bottom right. Take the door hidden in the wall to find a new room. Get to the bottom, toggle the On/Off Switch, and make it back to the top to collect the Key.
In the 7th room of Pizzaboy’s Pizz-Pizza, there are John Blocks to the right of the Treasure Room door. They deactivate during Pizza Time. There is a door inside the wall that leads to a new room. Get all the way to the right, toggle the On/Off Switch, and make it back without getting caught by the Sausage Toppin Monster to collect the Key. Don’t shoot the Toppin Monster before pressing the switch, as this will softlock the room and force you to replay the entire level.
The credits now show 6 new hints. You must complete them in this order:
The Key in the ceiling above John Gutter has made many upset. It looks obtainable, like its taunting you. Fortunately, it is possible, see the video below for help.