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