Here is the full list of all 84 OMORI achievements. It takes around 80-100 hours to unlock all of the achievements on Windows.
Reach the bad ending.
Reach the other ending.
Reach the good ending.
Go to SEAN and KAREN's housewarming party.
Give FLOWERS to MARI.
Defeat the RECYCLEPATH.
Trade CLAMS for CLEMS.
Have a ghost party.
Defeat HUMPHREY.
Defeat SLIME GIRLS.
Get the LOL SWORD.
Hold 99 TOFU.
Complete ORANGE JOE's quest.
Turn the valve to the right in RAIN TOWN.
Defeat KITE KID.
Defeat PLUTO (EXPANDED).
Defeat MR. JAWSUM.
Throw away something.
Defeat the PET ROCK champion.
Don't high-five KEL.
Defeat the HOOLIGANS with PEPPER SPRAY.
Take $20.00 from KEL's wardrobe.
Commission ROCOCO.
Defeat SWEETHEART.
Perfectly train the SPROUT MOLE choir.
Kill the first SOUS CHEF.
Ruin Christmas.
Choose the SPRING MOLE.
Choose the WINTER MOLE.
Choose the SUMMER MOLE.
Choose the FALL MOLE.
RELEASE ENERGY on your foes.
Water a plant back to life in BASIL's garden.
Go to sleep after a long day.
High-five KEL.
Pet a dog.
Complete the math worksheet correctly.
Complete all part-time jobs once.
Get a perfect score delivering PIZZA.
Quit in the middle of a part-time job.
Wake up in the morning.
Gain BREAD using BREAD SLICE.
Defeat SPACE EX-BOYFRIEND.
Defeat DOWNLOAD WINDOW.
Listen to MR. SCARETHROW's rant.
Make your way and talk to LONE MOLE.
Defeat THE EARTH.
Defeat ???.
Fly the BUTT CERTIFICATE in CATTAIL FIELD.
Complete your TO-DO LIST.
Get all rewards from the RECYCLING MACHINE.
Watch all movies in SWEETHEART'S "throne room".
Defeat the CHICKEN? at the top of DINO'S DIG.
Pet all the creatures in MARINA's sector in HUMPHREY.
Defeat 100 BUNNIES.
Defeat 100 SQUIZZARDS.
Commission all of ROCOCO's art.
Commission all of GATOR GUY's statues.
Let the plastic fish finish its song.
Take the KEEPER OF THE CASTLE's power.
Get the FLOWER CROWN from BASIL.
Recover at all of MARI's picnics.
Visit all mirrors.
Look through all telescopes.
Defeat UNBREAD TWINS.
Defeat SPACE EX-HUSBAND.
Defeat PLUTO and THE EARTH.
Defeat ROBOHEART.
Defeat MUTANTHEART.
Defeat PERFECTHEART.
Beat the BOSS RUSH.
Defeat every SOMETHING at the bottom of the LOST LIBRARY.
High-five KEL three times.
Brush your teeth every day.
Complete the grammar worksheet correctly.
Feed the STRAY CAT every day and sunset.
Lose to KIM and VANCE.
Battle the "bees".
Insert every song into GINO'S JUKEBOX.
Receive all FLOWERS in the hospital.
Read all the tombstones in the... dev room...
Enter code: haveadollariguess at www.omocat-shop.com for $1.00 off.
Unlock all achievements. Thank you for playing OMORI.
Complete the FOE FACTS! journal.