Jack'o'Lantern - on the table, next to Lily's bed


Midvinter book (if Jack'o'Lantern is not present) - on the table, next to Lily's bed


Fridge - downstairs


Cupboard - downstairs


Toy shelf - on the other side of the bed. (thank you, kayhmkay, for the tip)

Quitter
Try to leave the Cellar by going up the stairs


How to: Right after the intro scene, when you start level 1, try to go back upstairs in the house.
Suggested playthrough: #1


Thrillseeker
Pick the doll on level 1 after the monster appears


How to: Self-explanatory, pick up the key first so that the monster spawns, then the doll and then run to the exit while the monster chases you.
Suggested playthrough: #1


Cruel
You left the doll on level 1 after you found it


How to: Make sure to be in the proximity of the doll so that the story text pops up, but finish the level without picking it up.
Suggested playthrough: #2

Diggy Diggy Hole
Beat level 2 with all possible floor tiles collapsed


How to: First break the tile located under the car collectible (without going further up to collect the car), turn back and break the other tiles (by going to the extreme right, up, left, down), picking up the key in the end.
Suggested playthrough: #2

No Pressure
Beat level 3 without being hit by blowing steam


How to: Self-explanatory, avoid getting hit by steam.
Suggested playthrough: #1 or #2


Location: Go to the bottom left part of the map (the collectible is not visible right away) and then upwards by stepping on the breaking tile.

No Touchy
Beat level 4 without being caught by critter


How to: Self-explanatory, avoid getting hit by any critters.
Suggested playthrough: #1 or #2


Location: In a chamber with boxes located on the right side of the chamber that you reach by going straight down from the start of the level.

Tactician
Finish level 5 in under 7 seconds after you pick up the key


How to: After picking up the key, move a few pixels to the left (remaining pretty much in the same tile) so that the monster will start chasing you towards that side then quickly go right and down past the right critter. By taunting the monster and then changing directions you get enough time to escape it and reach the door. Of course, you will still have to time this with the critters' movement. It should be easily obtainable after 3-4 practice tries.
Suggested playthrough: #2


Location: Standing in front of the exit door, go left until you reach the end of the map.


Top left of the map:


Top right of the map:

Location: The top right of the map.

Location: on the top right part of the map there is a washing machine; go down the corridor that opens under it (watch out for the critter) and you will reach a niche with wooden boxes that partially hide this collectible.


Location: Bottom left of the map

Location: Finding this proves to be a bit tricky, even after several times of completing the level. Try to go on the right side of the teddybear (without picking him up), towards the right extremity of the map, then go up until you reach the top; start moving towards left until you see the pipe that covers the collectible is visible on your screen. Watch out for the critter that patrols under the steam pipe!


Location: Middle of the map, towards the bottom section

Nightmare Is Over
Escape the Cellar


How to: This achievement is not missable, you get it for completing the game.
Suggested playthrough: #1


What Are You Trying To Prove?
Finish the game without dying


How to: I would suggest doing this in a separate playthrough, without trying to collect the toys.
Suggested playthrough: #3

Amateur Toy Hunter
Find your first toy


How to: Self-explanatory, find 1 toy.
Suggested playthrough: #1


Journeyman Toy Hunter
Find 5 lost toys


How to: Self-explanatory, find 5 toys.
Suggested playthrough: #1


Expert Toy Hunter
Find all toys


How to: Find all the 10 toys in the game, not necessarily in the same playthrough.
Suggested playthrough: #1

Special Time of Year
You found one of the special seasonal events


How to: You will need to login and start a new game (in Normal mode for example) during one of the Public Holidays (Christmas / Easter / Halloween etc.). For example, 30 Oct worked for me.


Hard-boiled
Beat the game in Hardcore mode


How to: You will need to beat the game without dying, on Hardcore mode.
In case you need a bit of help, you could use this channel's videos (thank you Hoss for the tip)
https://youtu.be/1NkMwjE8OSI
Suggested playthrough: #4


Observant
Prove you have a keen eye and a nature of an explorer.


How to: For this achievement you are required to examine some special objects (for example washing machines, furnace, bycicle, workbench etc.).
Suggested playthrough: #1