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