Here is the full list of all 84 OMORI achievements. It takes around 80-100 hours to unlock all of the achievements on Windows.
Recover at all of MARI's picnics.
Unlock all achievements. Thank you for playing OMORI.
Reach the bad ending.
Reach the good ending.
Receive all FLOWERS in the hospital.
Insert every song into GINO'S JUKEBOX.
Feed the STRAY CAT every day and sunset.
Go to SEAN and KAREN's housewarming party.
Defeat the RECYCLEPATH.
Give FLOWERS to MARI.
High-five KEL three times.
Defeat the HOOLIGANS with PEPPER SPRAY.
Complete the grammar worksheet correctly.
Complete the math worksheet correctly.
Defeat the PET ROCK champion.
Complete all part-time jobs once.
Reach the other ending.
Defeat PERFECTHEART.
Beat the BOSS RUSH.
Battle the "bees".
Have a ghost party.
Read all the tombstones in the... dev room...
Defeat every SOMETHING at the bottom of the LOST LIBRARY.
Complete the FOE FACTS! journal.
Defeat MUTANTHEART.
Defeat ROBOHEART.
Defeat SPACE EX-HUSBAND.
Defeat PLUTO and THE EARTH.
Look through all telescopes.
Commission all of GATOR GUY's statues.
Visit all mirrors.
Let the plastic fish finish its song.
Take the KEEPER OF THE CASTLE's power.
Get the FLOWER CROWN from BASIL.
Complete your TO-DO LIST.
Brush your teeth every day.
Defeat HUMPHREY.
Defeat SLIME GIRLS.
Pet all the creatures in MARINA's sector in HUMPHREY.
Commission all of ROCOCO's art.
Get the LOL SWORD.
Trade CLAMS for CLEMS.
Defeat UNBREAD TWINS.
Complete ORANGE JOE's quest.
Defeat the CHICKEN? at the top of DINO'S DIG.
Quit in the middle of a part-time job.
Get a perfect score delivering PIZZA.
Turn the valve to the right in RAIN TOWN.
Defeat 100 SQUIZZARDS.
Enter code: haveadollariguess at www.omocat-shop.com for $1.00 off.
Watch all movies in SWEETHEART'S "throne room".
Hold 99 TOFU.
Get all rewards from the RECYCLING MACHINE.
Listen to MR. SCARETHROW's rant.
Defeat KITE KID.
RELEASE ENERGY on your foes.
Pet a dog.
Commission ROCOCO.
Defeat MR. JAWSUM.
Defeat PLUTO (EXPANDED).
Throw away something.
Take $20.00 from KEL's wardrobe.
High-five KEL.
Defeat SWEETHEART.
Perfectly train the SPROUT MOLE choir.
Kill the first SOUS CHEF.
Ruin Christmas.
Choose the WINTER MOLE.
Choose the FALL MOLE.
Choose the SUMMER MOLE.
Choose the SPRING MOLE.
Defeat 100 BUNNIES.
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.
Defeat DOWNLOAD WINDOW.
Defeat THE EARTH.
Make your way and talk to LONE MOLE.
Defeat ???.
Fly the BUTT CERTIFICATE in CATTAIL FIELD.
Gain BREAD using BREAD SLICE.
Water a plant back to life in BASIL's garden.