UPDATE: THANKS TO EVERYONE WHO GAVE TIPS. LIST IS COMPLETE NOW, BUT IF SOMETHING IS WRONG PLEASE TELL ME
I'm still going through the game for achievements and trying to beat the boss with a pistol (And suffering). So I'll update if I figure anything else out, but I thought I should put this up here in case someone needed help

This guide is in the rough order of when you can get the achievements, I've put the ones that you can do throughout the game, or the ones that need you to do things in multiple areas first however

Thanks to
Siroldas
anonymouseno1
KandyKannibal

For a walkthrough, check out RPGMinx's LP

- Collect all of the dead pictures

1 - Zombie: Let zombies kill Kio
2 - Giant: Let the anomatical models kill Kio
3 - Worm: Let the worms scattered through the game kill you
4 - Ghost: Let the first boss kill you
5 - Squeeze: Walk into the spike things ramming the wall in the dungeon
6 - Spike: First area, unlikely to miss, but you can also do it at the final boss
7 - Poison: Pull the switch in the room below the room that Illusion was killed in. Watch her suffer like a monster. Let the timer run out in the gas filled area after the library
8 - Saw: In the library, go down and head to the left from the panties. Walk into the saw
9 - Murder: Let Bobo kill Kio
10 - Big worm: Be killed by the worm spunk
11 - Rabbit: Follow Mr. Rabbit
12 - Monster: Walk into the ...teeth(?) in the library area. Let them kill you
13 - Falled Rocks: Be killed by the falling rocks at the final boss
14 - Fly Sword: (Walk behind the skeleton in the the building next to Bobo's, ignore what he says and walk behind him. Or stand on a purple tile when you get to the final boss)
15 - Laser: Let the final boss hit Kio when it's in it's second form
16 - Creeper: Let Kio be killed by the four-legged zombies

Find all the hidden rooms, use this guide if you need help

Beat the boss at bathroom
- Beat the boss at bathroom. Use the shot gun, move from left to right with the worm's face(??) in view at the top of the screen, when he shoots his spunk at you, move out of the way and then fire. Repeat until dead

Congratulations
- Beat the final boss. He has two forms so far, if he had anymore I am going to cry You can not take one hit here, you will die instantly and then you have to start all over again

Tips
Red: Cycles through patterns around the board, most common. Can duck through some tiles in the first few second but do it at risk to your own sanity
Blue: Appear in sets of four, one row apart. Rocks fall there, don't stand too close to the edge of it either, you can still get an instadeath. Can duck through them before the rocks start falling
Purple: Appear in lines that are either vertical or horizontal. Just move to the line the isn't coloured

First form: Don't touch the tiles that are changed to red, blue or purple or you get an insta-death. Go around and hit the buttons in all four corners of the room, if you have the patience, wait until you have a clear line through the tiles to get to him so you don't waste time

Second form: He begins moving from side to side, tile patterns remain the same. Wait to press the last button when he's close to you so you can whale on him

Third form: Stop and start when going from button to button or you'll be cornered to one side. He has three lazers, two from either side of his hands, and a giant one over about three tiles from his mouth. Go around and hit all but one of the buttons, then wait for him to use the mouth lazer as that's impossible to avoid if you were shooting, and then hit him, move out of the way, and keep hitting him until he bubbles up

Kick vending machine, use soda

Pick up chips, use chips

You must carry your phone all the way to the end. You can keep it in your storage and just add it to your inventory before the final boss for the achievement

Save the game

Get hurt

Die

In the area with the picture with slots for a head and heart, go past both offshoots of the main path until you get to a filing cabinet, which will show you a picture

In the spike room (In the dungeon where the door locks behind you). Run into the spikes before picking up the key

Touch the roach wall, you know you want to

Go to the other side of the key altar before shrinking the key with the gun

Shoot Sadako

Look at the map Illusion gave you until Kio gets jumpscared

Check the well in the area straight down from the save point in the library

Immediately go to the kitchen, check the fridge and click yes to picking up the key, and then check the trash heap so you can cut the rope with some glass

(Save in the bathroom before starting this so you don't have to redo anything for this achievo) After picking up the key from the fridge, head right for the living room without going into the toilet

When Bobo's at the front door, go up and touch the picture next to the lamp in the upper left corner of the room. You will need to memorise the path because you cannot wait for the light to come back on for you

Talk to the skeleton, then walk behind him

Wait for 5 minutes in the cat room (3rd hidden room)

Enter the building with the three eyed penguin on it. Approach the wall with the 3 eyed penguin and interact with it to get "Stupid Design"

Listen to the recording in the building with a "G" on it

When you are on the third floor of the school, choose to follow the rabbit here

Talk to Stan in the 9th hidden room

After going through the ice area and into the room with the...guy behind the glass, head back into the area and quickly skate on the ice and then just go back

Talk to Space in the 11th hidden room

Pick up chilli's in the aquarium, talk to Light in the 10th hidden room twice

Literally just don't use first aid kits, not even once, for the entire course of the game. Best method is to reload your save file if you get hurt. In the computer room with the two four-legged zombies, just accept a 20hp hit or figure something out, idk, I gave up. Also put your healing items away in the box so you don't forget and use them. Prepare to suffer

Suggestion from Sputnik
i hurry down to the one coming from the bottom and kill it with two shotgun shots and put the weapon away. I hope it’s helpful, cause it’s a shame to just throw away 20HP

Edit: You can use the bandaids, I learnt this after finishing the game, so I get the title queen of this achievement (and idiocy)

Beat the final boss only using a pistol cause ♥♥♥♥ all of us. See boss achievements for how not to die