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