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