If you haven’t play Chaos;Head Noah yet, I highly recommend you to experience it first, as Chaos;Child is a sequel to Chaos;Head.

https://steamhost.cn/app/1961950/CHAOSHEAD_NOAH/

Here’s my guide to Chaos;Head Noah: https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=3460869337

I recommend to install the CHAOS;CHILD Improvement Patch from Committee of Zero (https://sonome.dareno.me/projects/chaoschild-steam.html).

I am grateful to Kiri Kiri Basara for their guide which helped me master the game.

* The scheme does not show all possible girls’ points, but only that quantity which is sufficient to reach all routes.

Unmissable achievements mentioned in the scheme are not listed here.

At 1st playthrough only one route is available.

• Start new game.
  
• Select all delusions as negative, except following: ## 1-2, 1-8, 1-11 (see scheme). These 3 delusions select as positive.
  
• Solve all the Map Puzzles without making any mistakes. Make a save every time before attempting to solve a puzzle and reload it if any mistakes occur. See Map Puzzles’ Solutions section of this guide if you need (there obviously are spoilers).

After finishing the game you’ll get 11 chapter-related achievements (see scheme), [Over Sky End], as well as those:


Achievements: 14/34

• Start new game. Hint: when skipping, you can Alt+Tab the game, it will not be paused. The default skip settings are pretty good, don’t change them for now.
  
• Select all delusions as positive except 3 mentioned above: ## 1-2, 1-8, 1-11. These 3 delusions select as negative. Choose any available additional delusions.
  
• On Map Puzzle #1 give all the wrong answers and keep doing so until the "I Knew You Were a Wrong-Sider" achievement pops up.
  
• Make [Save 1] when delusion trigger #3-3 appears (before you choose the delusion!). Select delusion #3-3 as positive as well.
  
• Choose both incorrect answers on Map Puzzle #3 in order to get [Common Route Bad End]. Then load the last autosave and continue.
  
• In the Hinae Chapter, make [Save 2] when delusion trigger #H-1 appears. Continue to select all delusions as positive.

After finishing the game you’ll get [Dark Sky End] and


Load [Save 2]. Read through Hinae Chapter and select all delusions as negative. You’ll get [Arimura Hinae Bad End].

Achievements: 18/34

• Load [Save 1]. Skip delusion #3-3.
  
• Make [Save 3] when delusion trigger #3-4 appears.
  
• Select delusion #3-4 as positive, and select additional delusion. Skip all other delusions.
  
• In the Hana Chapter, make [Save 4] when Map Puzzle #8 appears. Solve the puzzle correctly.

After finishing the game you’ll get [Deep Sky End].

Load [Save 4]. Place all pins on the map incorrectly and proceed through the chapter. You’ll get [Kazuki Hana Bad End].

Achievements: 20/34

• Load [Save 3]. Skip delusion #3-4.
  
• Make [Save 5] when delusion trigger #4-1 appears. Skip delusion #4-1.
  
• Select all other delusions as positive and choose any available additional delusions.
  
• In the Uki Chapter, select delusion #U-1 as negative and get [Yamazoe Uki Bad End 1]. Then load the last autosave, select delusion #U-1 as positive, and continue.
  
• Make [Save 6] when delusion trigger #U-2 appears. Select delusion #U-2 as positive.
  
• Select delusion #U-3 as negative and get [Yamazoe Uki Bad End 2].
  
• Load the last autosave, skip delusion #U-3 and get [Yamazoe Uki Bad End 3].
  
• Load the last autosave and select delusion #U-3 as positive.

After finishing the game you’ll get [Dream Sky End] and


Load [Save 6] and select delusion #U-2 as negative, then delusion #U-3 as positive. You’ll get [Another Sky End].
Load [Save 6] and skip delusion #U-2, then select delusion #U-3 as positive. You’ll get [Yamazoe Uki Bad End 4].

Achievements: 23/34

• Load [Save 5]. Select delusion #4-1 as positive. You may skip other delusions you’ve already seen.
  
• In the Nono Chapter, select delusion #N-1 as negative, view it, then load the last autosave, select delusion #N-1 as positive, and continue.

After finishing the game you’ll get [Real Sky End] and


Achievements: 29/34

This final chapter of the VN (in fact, it could very well be Chapter 12 of the Common Route) will be accessible from the main menu (titled “TRUE”) after completing all mentioned above. Read through it and get [Silent Sky End] as well as


Achievements: 34/34

If you’ve completed all of the above and you’re still missing some CG/Tip/Sound and/or you still haven’t "I Am a Right-Sider" achievement, replay Common Route one more time, skipping all the delusions and making no mistakes in the map puzzles.

If you find any issues in this guide, please let me know in the comments.