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