Picking up the correct KEY will steadily fill in a message at the bottom of the HANGMAN interface (which can be accessed by pressing Q within HEADSPACE or by interacting with the laptop within WHITE SPACE) and inform the player how many correct KEYS remain. Incorrect KEYS will be discarded to the right and will cause a line to be added to the HANGMAN diagram.
All correct HANGMAN KEYS must be collected in order to complete the game's story. However, collecting all 26 KEYS is not required, nor does it affect the game's ending. Three KEYS (G, Y, and Z) can only be collected in the OMORI ROUTE, though all of them are incorrect.
|In the grass near a stump.||On the path to the FOREST PLAYGROUND outside of the stump that leads into the NEIGHBOR'S ROOM.||✓|
|On a shrouded old bridge.||On the FOGGY BRIDGE that connects the eastern and western halves of the VAST FOREST.||✓|
|Between giant pinwheels.||On a bench in PINWHEEL FOREST.||✓|
|Near a castoff cartridge.||Found on top of a garbage container in the JUNKYARD. Requires use of both OMORI's and AUBREY's ability to access it.||X|
|Underneath a wet pillow.||Underneath CAPTAIN SPACEBOY's pillow after defeating him in his house.||✓|
|Within a large frame.||Inside the BARN in OTHERWORLD's CATTAIL FIELDS.||X|
|Beneath a trap door.||Place the BATTERIES acquired from PINKBEARD inside the plastic fish within the FROZEN LAKE's IGLOO. Then stand in the center of the summoning circle in the unlocked basement. (Only available after HEADSPACE has been reset in the OMORI ROUTE.)||X|
|In a lost pyre's flame.||At the campfire in the end of LOST FOREST, the forest can be accessed past the SPIDER CAT area in PYREFLY FOREST.||X|
|Lying in a dark cell.||In a cell of THE DUNGEON within SWEETHEART'S CASTLE. Can be accessed via use of the underground passages.||X|
|Trapped in a pink cage.||In a cage within the QUARTERS (left wing of the second floor, past the KITCHEN) of SWEETHEART'S CASTLE. Use AUBREY to break the cage open.||X|
|In a hall of framed faces.||In SWEETHEART'S CASTLE's art gallery (left wing of the first floor, top-left door.)||✓|
|Far below a big stage.||In the LOST LIBRARY after defeating SWEETHEART.||✓|
|Spending time with a frog.||In the bottom of the well leading to the UNDERWATER HIGHWAY.||✓|
|Near a game of roulette.||Near one of the blackjack tables on the first floor of the LAST RESORT.||X|
|Amongst other O's.||In the bottom of the HAUNTED POOL next to the LAST RESORT.||✓|
|In a water closet.||In a stall in the MEN'S RESTROOM on the first floor of the LAST RESORT.||✓|
|In a small moving room.||In the elevator to the CONCIERGE of the LAST RESORT.||X|
|At the end of a plank.||At the very top of the CONSTRUCTION ZONE on the 4th floor of the LAST RESORT, back to FOGGY BRIDGE.||X|
|Within a live shell.||In a shell on the road between the toll booths of the UNDERWATER HIGHWAY.||✓|
|In a large bubbly tank.||Can be found in a container within HUMPHREY while being chased by EXPERIMENT 667. Use AUBREY to smash the glass. If not collected then, HUMPHREY will regurgitate it into DEEPER WELL after he is defeated along with the W KEY.||✓|
|Surrounded by goo.||Inside HUMPHREY during the water current section of the second bridge puzzle. Can be reached by turning left twice.||X|
|Captured in a steel trap.||Inside HUMPHREY during the multiple choice puzzle. Found in the first room inside of a cage.||X|
|In the gut of a whale.||HUMPHREY will regurgitate this KEY into DEEPER WELL after he is defeated.||✓|
|At the end of a map.||Inside DINO DIG, in the bottom-right pile on the 3rd floor. Use the TREASURE MAP as a guide.||X|
|In a field of white snow.||Found in a snowy field just before SNOWGLOBE MOUNTAIN proper near some pines. Keep going to the top-right of the map to find it. (Only available after HEADSPACE has been reset in the OMORI ROUTE.)||X|
|Past the end of the road.||Found at the end of the corridor in THE ABYSS. (Only available after HEADSPACE has been reset in the OMORI ROUTE.)||X|
Collecting all correct KEYS will spell out "WELCOME TO BLACK SPACE", which causes the floor of BASIL'S HOUSE to collapse. Choosing to jump into the resulting pit will cause OMORI to abandon HEADSPACE and enter BLACK SPACE, after which the KEYS will transform into the keys required to open the doors in BLACK SPACE.
Collecting all 26 KEYS will cause the completed HANGMAN figure to be covered by SOMETHING, after which the game will autosave and crash. Reopening the game will skip the title screen entirely and immediately load the autosave. Collecting all KEYS also allows OMORI to access the maze within THE ABYSS. Checking the HANGMAN menu after this will show the HANGMAN figure covered in a strange material.
After collecting most correct KEYS, a HOLE will spawn in the KEY's place. These HOLES will grow in size and can be interacted with in different ways as more correct KEYS are acquired, and are most likely the product of BLACK SPACE leaking into HEADSPACE. HOLES will disappear if OMORI leaves the immediate area, if they have been interacted with, or if OMORI TAGS another character.
The following is a list of events that occur if OMORI chooses to interact with the respective holes. These events are tied to the number of correct KEYS picked up, rather than the collection of any specific KEY. The appropriate event will occur even if OMORI has not interacted with any HOLES before, and there are zero consequences for interacting or not interacting with HOLES.
The L KEY does not leave behind a HOLE - thus only 11 KEYS are counted in this list.
- 1st and 2nd KEYS: Spawns a small HOLE that cannot be interacted with.
- 3rd KEY: Spawns a small HOLE. Interacting with the HOLE will ask the player if they wish to reach into the hole. Doing so will cause the screen to go dark, a brief noise to play and the dialogue "You felt a cold breeze."
- 4th KEY: Spawns a HOLE. Interacting with the HOLE will ask the player if they wish to reach into the hole. Doing so will cause the screen to display a faint image of two hands grabbing each other along with a high-pitched noise and the dialogue "You felt someone hold your hand."
- 5th KEY: Spawns a HOLE. Interacting with the HOLE will ask the player if they wish to go into the hole. Doing so will cause OMORI to fall for a few seconds before ending up in BASIL's room. Six pictures from the FARAWAY PHOTO ALBUM appear, all of which have been almost completely covered with scribbles made by a black marker. Leaving the room will return OMORI to his previous location in HEADSPACE.
- 6th KEY: Spawns a HOLE. Interacting with the HOLE will ask the player if they wish to look into the hole. Doing so will display a black screen dotted with the eyes of multiple SOMETHINGS, similar to the "SOMETHING drags you into the shadows" attack.
- 7th KEY: Spawns a large HOLE. Interacting with the HOLE will ask the player if they wish to go into the hole. Doing so will cause OMORI to fall for a few seconds before waking up in a black room, accompanied only by a television and two VHS tapes labelled "OMORI" or "BASIL" - though OMORI can only choose to play one. The "OMORI" tape shows SUNNY unhappily playing piano before looking at his reflection in the piano and slightly frowning. The "BASIL" tape shows BASIL looking down at the floor at first in confusion, then in horror as the camera zooms in towards his face.
- 8th KEY: Spawns a large HOLE. Interacting with the HOLE will ask the player if they wish to go into the hole. Doing so will cause OMORI to fall through a dark room with a watery background for several seconds, before falling into HELLMARI's mouth.
- 9th KEY: Spawns a large HOLE. Interacting with the HOLE will ask the player if they wish to look into the hole. Doing so will display a barely visible and vibrating picture of Sunny in the mirror with blood red eyes.
- 10th KEY: A black mass that forms into SOMETHING rises from the HOLE, after which the screen goes black for a few seconds, after which SOMETHING and the HOLE disappear. Unlike the other events, this happens automatically after the "1 KEY LEFT" message disappears.
- 11th KEY: Spawns a large HOLE. Interacting with the HOLE will ask the player if they wish to go into the hole. Doing so will cause OMORI to fall for several seconds before waking up within a isolated room within BLACK SPACE. The room consists of a narrow corridor and a small room. In the center of this small room is a tree with a noose dangling from it's branches, and the silhouette of a man chopping the tree down with an axe. Interacting with the figure, identified as "???" gives the dialogue "Stay away... You are not my son..." and interacting with him again will repeat the dialogue "Why... Why won't you fall?" The room can be left by walking towards the end of the corridor OMORI came in and interacting with it.
- When OMORI is close to correct KEYS, trails of bloody footprints can sometimes be seen leading towards the KEY. Their exact significance is unclear, though as SUNNY uncovers the truth of MARI's death in BLACK SPACE, he begins to leave behind similar footprints.
- The wall of SOMETHINGS image is reused in the SOMETHING boss battle.
- Cut frames still in the game files for the "BASIL" videotape show that BASIL is discovering MARI's corpse.
- A brightened version of the mirror image can be seen in BLACK SPACE as SUNNY uncovers the truth of MARI's death.