Right this game pretty much doesn't let you manually save, so it autosaves only at home, forcing multiple playthroughs. This is frustration is compounded by the fact that your actions may take days, ingame and irl to result in a desired outcome that will get you specific achievements.

Your save files are located here:
C:\Users\user name\AppData\LocalLow\HuaYiGame\DeliveryFromThePain

So alt-tab the game, and make copies of the save file into a new folder (which you'll name to keep it organized) to make your own save game files.

Disable steam cloud saves for the game by
right-clicking it in your library, click on properties,
and then updates.
Uncheck the box with Steam Cloud synchronization.

Also it's been over 6 months since I last played the game seriously, so I'm rusty at remembering stuff, and this guide is mainly a compilation of information gleamed from the forums and my own dementia ridden knowledge. Please comment if I've missed something or am mistaken with something and I'll update the Guide accordingly.

First of all before we proceed to spoilers the actual tips:
1) The important resources you want to buy from NPC are Steel(a lot), Copper Wire and Rubber in normal game.
In DLC you want Iron(a lot), Steel, Copper Wire, Food(if you are too lazy to harvest the lumber location)

The resources you want to sell are mostly same: Alcohol(it's very easy to craft and very important to craft in bulk for trading), Fresh food if it's in excess, Gunpowder(unless you go full ranged and do not use melee at all, then keep gunpowder, otherwise you get more than you need if you use it for bosses mostly), plastic(there is more than you need in game, but don't go overboard selling it too).. also 'used up' books and other used up stuff that stays with you.

2) Focus on getting car ASAP it will make moving around much faster and safer.(there is a guide for it https://gtm.steamproxy.vip/sharedfiles/filedetails/?id=1350807695)

3) It's extremely important to attack enemy from behind - most enemies die to a hit from behind... this also saves durability of weapons.

4) Make upgrades smartly - you first want to focus on stuff that will make your overall life easier - needing to sleep less with good bed, not needing as much food with your own garden to grow potatoes.. shower is also extremely good mood increase, only needs water and water pump is super cheap to repair.

If you didn't read it earlier, yeah, there will be spoilers.

You can generally get these by going through the game.

Big Bang & Small Gang
Power Plant Detonation & Next day Assembly

To get to North city, you will need to blow up a power plant, you cannot turn off the power, it's blowing it up or nothing.
Time-bomb materials:
They appear randomly in one of the following places.
Power-Plant, Youth Hostel, San Salon Police Station, Central Shopping Square
by lu_pp
After that, Big brother will visit you, demanding you be present for an assembly. Just go to Central Park after that.

Beware Monsters
Spider Queen VS Player - Stronger Monster Evade & Big Brother Met

She can be found in the Automobile factory. kill her, and survive the encounter with the other monster that comes along(by running away, wussy style).

Unmissed Mist
Toxic Fog Collection - All Fog Areas

Collect the Fog from locations in North City. This is a quest. No need to run around and suffocate, until you get it from Big brother/Avery or Doctor Duke.

If you don't feel like coughing up your lungs, craft a gas mask.
Mask materials:
They appear randomly in one of the following places.
Wilfred Sanatorium, Salem Mart, Orm Mall, Beauty Green Inn, Tim Johns Police Station
by lu_pp

Unforgiven
Assembly Avoided - After Power Plant Detonation - Death by Big Brother

Basically, don't show up when you're asked to assemble after blowing up the power plant.

Splash of blood
Assemble 1st Melee Weapon

Study or research what you need to assemble a melee weapon. Then make sure you have a workshop to craft it.

Hey! Here I am
Assemble 1st Ranged Weapon

Study or research what you need to assemble a ranged weapon. Then make sure you have a workshop to craft it.

Colin Loke - a guy who will come by your house and ask to stay with you - do agree to let him stay, he is gonna be a merchant so you can stock up on essentials I mentioned from him.
Location: Your home, Big brothers home(after moving to north and some time passes)
Cannot die/leave through story.
By Hentaika

-Thief, dirtbag, apparently a good guy. One of the other very likely to survive characters.
He spends his time sticking his nose in other people's business, like you.
Location: Gets around. Your house, and Big Brother's.

Odd Odds
Car to Drive - Meet Loke 1st Time - Roommates

He arrives at your house. Usually after you get a car. Hangs out a few days, sells you stuff,Then steals your stuff before leaving without notice.

Black & White
See Loke Giving Medicine to Catherine in the Police Station

Visit Catherine a lot, you see him.

Ulterior Motive
See Loke at Big Brother Home - Persuade Moira Leaving Big Brother

If he's not at your house, he'll be at Big Brother's

Best Laid Plan
See Loke at Automobile Factory - Loke Persuades Big Brother to accept Catherine

Big Brother's hangout later in the game. I assume Catherine is still living with you, or in the police station.

Inviolable
Day After Assembly - Loke Cons Avery & Big Brother Scolds

Disagree with Loke when he visits Dr. Duke, make Avery do Decryption Mission instead. Big Brother will scold him the day after the assembly. - Woojin.

Adamant
Loke Tricks Fail - Final Door Exit Barred VS Player

Disagree with Loke few times (2-3) - Woojin.

Behind Lurks
Loke Tricks Fail - ID Theft VS Player

Don't let him stay in your base. Disagree with Loke all the times, must include doing Inviolable achievement. - Woojin.

Loke Lives!
Finish Game - Loke Survives

He's difficult to kill.

- the small brother weapon merchant.
Location: Central Park, Big Brother Home.
He can die - first time you can certainly save him. Once Big brother disappears from automobile factory - you will be able to find him in big brother's condo, injured. BEWARE, once you are inside - you need to finish this location by rescuing Avery from 2nd floor or he will die(you can loot it later, no worries) so come prepared.
After his rescue in some days he will visit you - telling that he wants to do something by himself.. it's a sign that he is in trouble again. You can find him near Air suction in Automobile Factory(air suction is in location to the right) I found him after some time and he died in the process, not sure if he stays alive if you do it faster or there is some other hidden condition.
by Hentaika

Avery Averted
Big Brother Condo - Avery Unaided - Player Fail

The Condo building will be unlocked when Big Brother gives you a quest to get Little brother. Fail miserably, by letting zombies get his brother or just don't save the guy. Have a good laugh.

2nd Chances
Rescue Avery in Big Brother's Condo

Successfully get Avery out of the condo. Best to kill everything that moves, then speak to him.

Strange Change
Avery Injured - Strange Change - Met in Automobile Factory

After Avery visit your base, dont save him until at least 6 days later. Also don't visit Big Brother's Home. - Woojin.

Discontinued
Failed Escourt - Avery Dead - Automobile Factory Escourt Fail

2nd Encounter, he'll need help again and will be found in the Automobile factory, same deal, let him die.

Residual Value
Save Missing Avery at Automobile Factory - Player Escourt

Make sure you've got your gas mask. You'll need it.

Gimme Gets
Avery Dealings - Asked & Agree to Gifts

Avery sidequest, talk to him for it.

Avery Always
Finish Game - Avery Survives

Saving him twice does the trick. See 2nd Chances and Residual Value achievements.

- sells steel and copper wire(most important resources)
Location: Automobile Factory
He can't die and will stay till the end.
by Hentaika

Bonds of Brotherhood
Discuss Big Brother Outlook Change & Discuss Avery Escape Option(s)

If I remember this right, it's after saving Avery, and you chime in when they discuss escape options together.

Valhalla Bound
Eulogy & Battle Cry - Big Brother Regrets & Charges - Battle Climax

Avery dying should be a prequisite to this.

Big Brother Begins
Finish Game - Big Brother Lives

It's hard to kill him, but it's possible, via the Cathrine's revenge subplots and dying to the last boss.

- doctor, sells medicine.
Location: Smith Hospital, Central Town Park(before noon), Wilfred Sanatorium(after moving to north)
He will leave permanently if Hunter Miller dies.
-by Hentaika

Weird Scientist
Dr. Duke Met at Smith Hospital

He's on the North-East door in the Hospital

Upbeat Uplink
Dr. Duke given Positive Topics in Dialogue

Be nice and talk about whatever he wants to talk about.

Exterminator
Dr. Duke Zombie Cull Mission by Player

He asks you to do something, do it.

Seek & Find
Dr. Duke Lab Equipment Mission by Player

go geddit. It's in another Medical place.

Fetch & Carry
Dr. Duke Lab Equipment Mission by Player - in Wilfred Sanitarium

Go geddit in the Sanitarium, meaning, no lab equipment, until after he moves to North City.

Kill the Engine
Dr. Duke Auto Fix - Player VS Monster

Part of getting the car. A better guide was written here. https://gtm.steamproxy.vip/sharedfiles/filedetails/?id=1350807695

Voltage Vamoose
Dr. Duke Decryption & Power Plant Escourt

When Duke's in the power plant, escort him without killing him.

Wasted Effort
Failed Escourt - in Dr. Duke Power Plant Decryption Mission

He dies while escorting him around. Good job. Proud of you.

Fragile Psyche
Big Brother told Dr. Duke Gone - Blame Player Sarcasm

To make him give up research: don't choose option "have some little chat" with him until he moves to Wilfred Sanatorium, then keep chatting with him and choose the options that ♥♥♥♥ him off. After all the discussions (probably 10), he will leave in a few days.
-By Falka

Science Frontier
Big Brother Tells Dr. Duke Quit Research - Wilfred Sanitarium

Just keep talking to him and be nice. He will leave eventually, needed to get "Desperate Truths" Achievement. - Woojin.

Desperate Truths
Dr. Duke Suicide in Special Lab

For people who also look for this: I think you must first get the achievement where Duke gave up research or went away because of sarcasm, then get the good ending.
By Falka

Dr. Duke Durability
Finish Game - Dr. Duke Survives

Keep miller alive, don't be a ♥♥♥♥, that's about it.

- food merchant.
Location: Residence(not far from your base), Old House(during his quest chain, his mama house)
Okay, this one can VERY easily die.
I did not manage to make him stay alive until the very end but I got pretty late into his quest chain, do tell if anyone got further.
Quest to save him: during the meeting in central park(big brother meeting) tell big brother than he is a better man than petty killer.
Now you need to wait a day and go to residence first thing on the next day. Big brother will be there and won't kill him, telling you to persuade him to go north..
From now on keep visiting him daily, eventually he will ask for a teddy bear from old house... give it to him. With teddy bear in hand he will explore the next day and get injured, you will find him in Central Park. Give him 5 bandages/splints. From then on he should move to old house(if he isn't - check residence)..
EDIT: Apparently you need to solve his quest before doctor moves into north hospital.. basically don't talk with doctor at all until you solve hunter miller quest.
by Hentaika

In the Thick of It
Miller 1st Met

Meet him at the Residence.

The homebody's love
Miller's Video-Game Mission Success

The homebody's love - In Chapter 1, trade with Hunter Miller several times (maybe 5 times) to trigger this quest. -lu-pp

Twist of Fate
Miller Residence - 2x Back Loke for Miller Move North

You gotta visit him daily, and keep trying to convince him to move. Back Loke each time Loke tries to convince miller to move North.

Tobey
Miller Teddy Bear Mission

Miller wants a Teddy Bear gogeddit. Go to Catherine and Angel, they want the bear too, so give it to Angel which gets the Sweet Dreams achievement, and then kill yourself, reload the day, and give it to Miller, tell Catherine the truth, getting yourself the Sincerity Achievement.

Eat or be Eaten
Miller Saved - Central Town Park - Player VS Monster

Miller goes around to Central Town park after the resolution of the teddy bear quest, and will get injured. If you're visiting him daily, you'll have noticed he's not at his house. Save him from a monster. And bring 5 bandages/splints for the next achievement.

Binding Ties
Miller Saved - Central Town Park - Player Bandage / Splint Same Day

See Eat or be Eaten.

Out of ammunition and food supplies
Miller Starves - after Player met

His food goes bad eventually.

Keep buying his stuff in chap 1 and chap 2. - Woojin

Misfire
Miller Shot - Missed Assembly & Big Brother angst & Player Fail

Self-explanatory.

Miller Mauled
Central Town Park - Player VS Monster Fail

Fail Eat or be Eaten.

Die before Heal
Miller RIP - South City Park - Player healing Fail Same Day

Failing the achievement Binding ties will get you this one.

Those Against Me
Miller Shot: North City refusal, Big Brother Angst & Player Fail

Failing to convince Miller to move within Big brother's deadline will net you this achievement.

Miller's Leftovers
Scavenge Miller's Items - Postmortem

Miller has to die, obviously.

Miller Time
Finish Game - Miller Survives

I was able to get Miller to survive by getting him to North City, and giving the Teddy bear to him, telling Cathertine the truth about it, saving Miller and checking up on him daily in general.

-Professionally pointless existence.
Location: Big Brother's house.
No one cares about her, nor does anyone like her. Big Brother's "sidepiece."
Really seems proud of that too.

Moira Moreover
Finish Game - Moira Lives

If you see Big Brother and Moira talking at Big Brother's home... don't engage their conversation... then Catherine will be ok and Moira will not die... If you engage their conversation then Moira will leave the next day and Catherine will move to the north and end up both women die
by OmniaFacimus

- a woman and her daughter.
Location: San Salon Police station.
Don't seem to be able to die, at least I never did anything out of ordinary for them and they were fine, in dialogues I tried to be supportive of them.
Maybe there is some way to die if you don't try to keep moira/catherine relations out of check, but nothing serious happened for me.. I first made them stay with me in south city and they only moved north quite late, this made catherine/angel/moira all survive.
By Hentaika

During the meeting after bombing the power plant, tell Duke it's dangerous for Catherine to go to the north (choose 1) Then she'll stay where she is and don't let the young guy convince BigBrother's girlfriend to leave... I might be wrong for I'm still playing
by OmniaFacimus

Unveiled
Catherine ++ Visits- Angel's Question answered with Love Confession

Cloth is quite a redundant resource, give it to her, and visit her enough times, then talk to angel and confess your desire to be her mother's sugar daddy.

Tactless Tactics
Catherine ++ Visits- Angel's Question answered with Insult & Apology

Cloth is quite a redundant resource, give it to her, and visit her enough times, then talk to angel and confess your resistance to being a cuck, then be a cuck.

Little princess
Angel gets Princess Dress Gift from Player

The Dress should be found at a mall, give it to Angel before she moves to North City.

Glitzy Girl
Angel Gets Princess Dress - Gift from Player - North City

See little princess, give the dress to Angel after getting them to move to north City.

Just Say No
Catherine Given Princess Dress - Refuse Gratitude Before Move to Big Brother Home

Don't take rewards from her, do her quests out of the Kindness of your heart, and a healthy fear of STDs. You simp.

Sweet Dream
Angel gets Tobey Teddy Bear Gift from Player

Crosses with Tobey Achievement and his quest. She's got her damn dress, the bear is Miller's.

Sincerity
Catherine Told Truth of Tobey Given to Miller

Give the bear to Miller, tell Catherine the truth that you gave it to Miller.

Travesty & Tragedy
Catherine & Angel RIP - Police Station Defense Fail

Have both Characters die as a result of failing the Police station defense. Hang out with them frequently, the police station defense is usually triggered by progressing the story, or intervention by the other annoying lady, Moira.

Road to Revenge
Angel RIP & Catherine's revenge - Police Station Defense Fail

Failing the police station defense that gets angel killed, usually by arriving late, results in this, which will tie into the Character Conflict achievements section.

Northbound
Catherine & Angel Move to North City & Police Station Defense

After successfully defending the Police station, convince Catherine and Angel to move North.

Angel's Tread
Catherine RIP in Home Defense & Angel to Playe

Offer that Catherine and Angel stay with you after the assembly and around the time of the First police station defense, if she refuses, you haven't been simping enough. Then Neglect walls and traps at your own home until you manage to force a Home defense Mission.

Mother & Daughter Dawn
Finish Game - Catherine & Angel BOTH Live

Survival is relatively simple. Not Speaking to Moira/watching her leave Big Brother's house. Keeping Catherine and Angel alive, either at your house, or the North City Police station. Above all, do not let her hang around Big Brother.

If you see BigBrother and Moira talking at BigBrother's home... don't engage their conversation... then Catherine will be ok and Moira will not die... If you engage their conversation then Moira will leave the next day and Catherine will move to the north and end up both women die...Don't visit Catherine when you've gathered all the 4 magazines for the code to enter the 'good ending' room
by OmniaFacimus

I've reserved this section specifically for cross-character conflicts, for you to open up a tab and check out exactly what you're going for when you see several characters together.
Angel's death should be the Catalyst for most of these achievements. Angel dies of two primary ways, through moving in with Big Brother, or a failure to defend the Police station.

Gift of Gab
Dr. Duke - Avery Met - Dr. Duke Helps

Avery will discuss the plan to open the path to North City. I think Loke helps you convince Duke to go to the power plant to try to shut down the power. Being acquainted with both of them prior to this should help.

Cat Fight
Catherine VS Moira Spat - Witness

You get this after the Assembly

Timely Arrival
Catherine VS Moira - Latter Met & Former Defended - Police Station

Pick a neutral choice when Moira question Catherine at the assembly (the 2nd choice). Choose to participate when Moira visit your base. - Woojin

Heart of the Matter
Discuss Spat - Big Brother & Moira - with Loke

This is the achievement you do not want to get if you want to keep Catherine alive. Just don't talk with Moira or Big Brother when you see them all together.

Last Rites
Catherine VS Moira - Death & Suicide - Recollect at Big Brother Home Grave-sites

Having Moira and Catherine in Big Brother's house should get this result, either by Catherine and Angel Moving there, or by Angel dying in Police station defense. Go find their graves.

Women's War
Catherine VS Moira - Both RIP - Big Brother's Home

See Last Rights.

War of Attrition
Catherine VS Moira - Moira Wins

Don't for simp Catherine, pick neutral choice at the assemble. She will give up barbing Catherine after a quarrel with Big Brother. - Woojin.

Eye for an Eye
Catherine VS Moira - Death & Suicide - Battle Climax

When Catherine decides to get revenge, she will come before the final battle to kill Moira.
This requires Moira to stay in Big Brother's Home and Avery to die/not be saved. - Woojin.

Last Bullet
Catherine DOA - Catherine VS Big Brother & Avery Fail

See "Eye for an eye", Requires Avery alive. - Woojin.

Evermore
Moira & Big Brother DOA - Moria Exit - Both RIP - Battle Climax

Enter the final battle when Moira is still leaving Big Brother's Home and Avery is dead. He leads the charge in final battle. - Woojin.

Disservice
Catherine VS Moira - Catherine RIP & Loke Visits

Loke Should visit after the woman's war achievement. He'll have something to say. - Woojin.

No survivor
Finish Game - ALL NPCs & Player Die or Escape

See each Character Achievement section for conditions that result in a character's death.

Amazing Grace
Finish Game - ALL NPCs & Player Survive

Mother & Daughter Dawn, Moira Moreover, Big Brother Begins, Avery Always, Dr. Duke Durability, Miller Time and Loke Lives! Are achievements associated with this one.

Endless Pain
Special Plot - Withdrawal Before Climax Battle

As the achievement says.

After explaining to Big Brother that the decisive battle is about to begin, the special plot produced by not participating in it. Wait for a few days in shelter (and re-enter) to trigger it. - Woojin

Bad Ending 1
Finish Game - Normal or Hard Difficulty.

Do everything as told, after final boss simply use ID in automobile factory to escape via main door...

Bad Ending 2
Finish Game - Nightmare Difficulty

Same as bad Ending 1, but on Nightmare difficulty

Good Ending
Finish Game - Best Plot Ending & Secret Discovered - Any Difficulty

Do not activate the generator near secret door in police station. Find 4 journals to get the password, use the ID card from last boss to open this secret door along with password from journals.

Bad Ending 3
Finish Game - Worse Plot Ending & Escape Refused - Any Difficulty

After you kill the last boss, wait for a few days in shelter (and re-enter) to trigger the special bad ending. Any difficulty. -Woojin

Special Ending
Finish Game - Special Plot Ending - Any Difficulty

1. Get Catherine/Angel to move to North City.
2. Ensure the safety of them both during defense, when their police station(either one) gets sabotaged.
3. Due to a cutscene, Catherine will die, leaving you to take care of Angel.
4. Feed Angel dainty potatoes every day until she tells her last story.
4a. Her last story will present you with a choice, pick the third, non-binary choice.