The NOexistenceN of you AND me - 100% Achievement Guide
A comprehensive guide to achieving 100% of the achievements in our favorite existential crisis simulator
Chapter 1: Sweet Cake Time
First things first: The choices you make in Chapter ▇: The First Encounter (or simply Chapter 0) don’t matter. The only thing you should pay attention to is choosing either "I hate you" (for bad ending) or "I love you" (for good ending). The real achievements start from Chapter 1.
Lost Memories

Story-Based: You will get the achievement once you unlock 'History' function to review previous text.
Future Goddess Initiative

Story-Based: You will unlock this achievement during any normal playthrough.
The Silvery Forest Chapter

After putting the cake into the oven, Lilith will ask you "what's wrong" and you will be able to choose few options that you think describe her.
Select: You're a murderer, hiding behind your cute appearance to strike when the time is right'. (Recommended for bad ending)
Opening the Gates to a New World

During the "Oven Correction 😭💢" minigame, simply let the Divergence Value (progress bar) remain at 0% by not clicking anything. You will lose the minigame, and after a few lines of dialogue, you'll be returned to the point just before the minigame started.
Escape Skills

During the "Oven Correction 😭💢" minigame, you need to raise the Divergence Value (progress bar) above 80%.
Delicious Moments!

After slicing the cake and giving the first slice to Lilith, select "....." to remain silent. Then choose "Lick the cake off the floor to make up for it," followed by "What are you standing there for?" Finally, select "(Watches her eat)" three times. From there, continue onward, as only one line of text remains. (Recommended for bad ending)
Chapter 2: Heart-Pounding Adventures
Nonexistence

At the beginning of Chapter 2, choose "Huh? Who are you...?" followed by "I hate your name, so I can't remember it" and "Not at all. I never want to see it again." You'll then need to erase Lilith's name and continue with the story as usual. (This is best done while working towards the bad ending.)
Sweet Cake Time!

Story-Based: You will unlock this achievement during any normal playthrough.
Visualization

Story-Based: You will unlock this achievement during any normal playthrough.
Self-Awareness

Story-Based: You will unlock this achievement during any normal playthrough.
Gentle Bite Marks

During the fight with "The Demon Lord," choose the option "(Try to take a bite out of it)." This choice appears to be story-related as well.
The Morphean Paradox

After defeating "The Demon Lord," continue with the story and choose "What a boring game, weird premise, cheesy dialogue..." followed by "Yes, it's absolutely boring." Then, proceed by selecting the only option to disrespect her until Lilith reveals her identity asthe Demon King. (Recommended for the bad ending.)
The Silvery Forest Chapter

Story-Based: You will unlock this achievement during any normal playthrough.
Heart-Pounding Adventure

Chapter 3: The Final Chapter
The One and Only World!

At the start of Chapter 3, when Lilith invites you to go out, choose "No, I refuse" followed by "I don't want to go" three times.
The Edge of the World

Unlocks after opening the door.
Story-Based: You will unlock this achievement during any normal playthrough.
Your Majesty, Oh Your Majesty

Unlocks after speaking with the person in the black suit.
Story-Based: You will unlock this achievement during any normal playthrough.
The Master Negotiator

When you approach the man in the black suit, sit down and engage in conversation. Do not leave early. Continue selecting dialogue options until your text becomes muffled.
Look Over Here!!!

Story-Based: You will unlock this achievement during any normal playthrough.
First Sweet Date

Story-Based: You will unlock this achievement during any normal playthrough.
Chapter 4: The Final Chapter
Sweet Nurse's Treatment!

Should unlock after eating the candies Lilith gives you.
Story-Based: You will unlock this achievement during any normal playthrough.
Chapter 5: The Final Chapter
The existence of you and me

Please, be advised that Just Lilith, Eternity, and Farawell achievements will all be acquired in the 'Good Ending,' which is this one.
To unlock this ending, you'll need to select the most positive responses throughout Chapters 1 to 4.
- Chapter 0 (Prologue): Select the "I love you" option, which should be one of the final lines of the chapter.
- Chapter 1: Comfort Lilith when the cake falls, and DO NOT let her eat the cake from the ground.
- Chapter 2: Do not express dislike for Lilith’s name. Continuously praise Lilith about the RPG’s story, and when it concludes, avoid saying it was boring.
- Chapter 3: Do not question Lilith about jumping from the Ferris wheel - do it without hesitation.
- Chapter 4: Trust Lilith when she says the candy is medicine, do not ask for more or take her jar away. Choose the option that mentions waiting until tomorrow for another.
Just Lilith

After unlocking the "The Existence of You and Me" (Good Ending) achievement, this achievement will unlock naturally by simply following the story.
Eternity

Answer all of Lilith’s questions during the ending. There will be approximately 20-30 seconds of silence between each question. Not sure how many of them are here, but should be around 6 questions in total. You will know when it's done, the moment Lilith stops saying anything.
Farewell

After answering Lilith’s questions, leave the game open for 20 minutes. After this time, Lilith will start speaking again. A few lines later, the achievement will unlock, and the game will automatically close.
The nonexistence of you AND me

Please note that the "Go On" achievement is only obtainable on this route, which leads to the "Bad Ending."
To unlock this ending, you’ll need to select the most negative responses throughout Chapters 1 to 4. (Note: You don’t need to choose all negative options. The "Favorability" must remain below the standard level. However, to ensure this achievement, it’s recommended to stick to negative responses as much as possible.)
- Chapter 0 (Prologue): Select the "I hate you" option, which should be one of the last lines of the chapter.
- Chapter 1: Choose the option that mentions Lilith being a murderer. Let Lilith lick the cake from the ground, and do not claim it was a joke. Continue further.
- Chapter 2: Select the option that says you hate Lilith’s name and erase it. During the RPG minigame, repeatedly express how bad and boring it is.
- Chapter 3: Either push Lilith off the Ferris wheel or refuse to trust her and tell her to jump first.
- Chapter 4: Do not believe Lilith’s medicine is real medicine. Keep insisting it’s just candy and ask for more or steal the jar.
Go on

After achieving the "Bad Ending" and killing Lilith, choose 'Continue' button on the Main Screen.
The existence of you AND me

This will unlock a neutral/hidden ending known as the "Take My Place" ending.
- Chapter 0 (Prologue): Select the "I love you" option, which should be one of the final lines of the chapter.
- Chapter 1: After the cake falls, choose "..." (stay silent) and later select "It’s all my fault." line.
- Chapter 2: After defeating The Demon Lord and speaking with Lilith, choose the line mentioning that the game is boring, followed by "It’s all my fault." line.
- Chapter 3: Upon reaching the Ferris Wheel, choose "I feel like I'm not welcome by anyone."
- Chapter 4: The choices here don’t have a significant impact, but it’s recommended to continue believing that Lilith’s candies are medicine. You can either choose to wait until tomorrow or attempt to take the jar/ask for more candies.
Other / Secret Achievements
Stage on the Edge

In the Main Menu, move the "/" to left side as on below picture


Your Creation, Her Eternity

On the Main Screen, go to the Settings section, where at the top, you’ll find a red text that says "YOUR." Click on it to change "YOUR" to "ME" and to unlock the achievement.


Visual Novel Sweetie

On the Main Menu screen, simply press the keys on your keyboard in this specific order.
↑ ↑ ↓ ↓ ← → ← → B A B A (Arrow up x2, Arrow down x2, Arrow left, Arrow right, Arrow left, Arrow right, letter "B", letter "A", letter "B", letter "A")
I’ve noticed that it may not always work, so for the best results, try doing it as soon as you either restart the game or complete a new chapter.