All the achievements were obtained from the following guide. All credit goes to dotHacker.
Go uprate his guide.

https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=1841111483
Please note that one achievement requires a working microphone.

Start a New Game.

• Input 378 at the login screen and confirm.
  
• Click the boxes:

ㅤ│ > 10 times
ㅤ│ ^ >
ㅤ│ > 5 times
ㅤ│ ^ >
ㅤ│ > 7 times
ㅤ│ ^ >
ㅤ│ >
ㅤ│ ^ >
ㅤ│ >
ㅤ│ ^ >
ㅤ│ > 3 times.



   A microphone is required for the next achievement.

• Hover over the bottom of the screen and click on Programs → Pong.
  
• Click the microphone icon at the top right corner → pull the cord that comes down → and plug it into the "microphone hole".
  
• Plug in a microphone if you haven't yet and make noises to lift the paddle up or stay silent to do the opposite.
  
• Win by scoring 5 points.

• Type "clippy" (without quotes) on the desktop.

• Hover over the bottom of the screen and click on Programs → Numbers.
  
• Win at the multiplication tic-tac-toe mini-game by matching 4 consecutive numbers in the grid in horizontal, vertical, or diagonal fashion.
  
• See screenshot for an example.

• Hover over the bottom of the screen and click on Programs → Mines.
  
• This is anti-minesweeper game: win by finding all mines (first click is free).

• Click on the Bluetooth icon at the top right corner.
  
• Arrange the dots to draw the following shapes:

• Click on the battery icon at the top right corner.
  
• Use ← and → keys to play.
  
• Lose with 5 points for one achievement.

• Play again and cumulatively score 25 total points (so just 20 more since you already got 5 from the previous achievement).

• Idle for 60 seconds at the desktop screen to make a screensaver animation pop up. Now wait until the screensaver icon bounces into a corner to unlock an achievement (the whole process can take 5+ minutes).

Thanks SomeMugger for the clarification.

• Open Portal 1 (Programs → Portal 1) and Portal 2 (hover over the bottom → Portal 2) and then complete the mini-game.

• Solution:

ㅤ│ 2D L U R D R
ㅤ│ D R D 2L D 2L
ㅤ│ U R 2U 2L 2U R
ㅤ│ U R D R D 2L
ㅤ│ 2U R D 2R

• Click the white dot at the center of the screen to return to the login menu.
  
• Input the following numbers:

ㅤ│ 733
ㅤ│ 737
ㅤ│ 783
ㅤ│ 787
ㅤ│ 833
ㅤ│ 837
ㅤ│ 883
ㅤ│ 887

• Make a perfect square by click and dragging/dropping anywhere on the desktop.
  
• You'll get a percentage after each medium-sized square.
  
• Reach 100% to get the achievement.

• Click on the top left corner to access the Start menu
  → Support.
  
• Redo the support icon by lighting up all but the very bottom segment.
  
• See screenshot for an example.

• Now, your next task will be to solve all the white nodes in order to finish the game.
  
• Click on Start menu → Find → and mark the following words:

ㅤ│ This
ㅤ│ World
ㅤ│ Story
ㅤ│ Page

Example:


This is just an example; this puzzle is randomized for each playthrough.

• Click and hold the bottom right corner and drag to the left, as if the desktop was a page.
  
• Go through each page to unlock the achievement:

• Click on the clock (top right corner) → green button on title bar → rotate the left handle until the red ball reaches the left end.

• Right click anywhere on the desktop and change background color.
  
• Choose:

ㅤ│ Red
ㅤ│ Cyan
ㅤ│ Yellow.

• Right click again and create a new folder.

• Grab the question mark [?] and drag it to any of the corners of the screen.

• Click on Start menu → I, about me.
  
• Hold in your keyboard the letters marked in red to climb up (can only hold maximum two at once).
  
• Once you reach the numbers, make your way up to the 5 and then grab the 9.

• Click on Start menu → Shut Down.
  
• Make a bridge using the blocks to light up the C, L, O, S, and E letters.

Solution:


Move left once to finish the puzzle.

• Click on the trash bin and solve the jigsaw puzzle:

• Click on Settings (bottom icons) → Cursor → choose the Mouse (fourth one).
  
• Click on the browser icon → visit www.bostan.com → Try FREE version.
  
• Hover over the circle next to "I'm a mouse".

• Click on Settings → Camera → Enable.
  
• Click on the top notch to access the camera → press spacebar.
  
• Destroy black squares until completing the task (start with the top ones; progress can be checked on the bottom red bar).

• Click on Programs and drag & drop to sort all icons alphabetically:

• Click on Programs → Cleaner → Start by clicking the right arrow.
  
• Drag the window around to help the dog clean the black hexagon.
  
• Repeat until completing the task.

• Click on Programs → Guitar.
  
• Click the microphone icon at the top right corner →
  pull the cord that comes down → and plug it into the speaker hole.
  
• Adjust the circles on the ring so the lines don't intersect each other.

• Click on Programs → Paint.
  
• With the help of the black squares (click to place and remove), paint the field like in the screenshot.

• Click on Start menu → Sleep → reach the end of the maze.

Example:


This is just an example; the maze is randomized for each attempt.

• Click on the map marker icon (bottom of the screen) and solve the puzzle by dragging the pins to form the word "mothernature".

• Click the nodes until finding the one in screenshot (relaunch game is clicking the nodes don't work; thanks YouGotHitByGunner for the tip!)
  
• Click on "download this update".
  
• Solve all three levels:

ㅤ│ Level 1: Stand in the blue floor and hold ↑.


ㅤ│ Level 2: Rotate the rightmost green floor to reveal a hidden passage.


ㅤ│ Level 3: Climb up the left wall and then make your way through the ceiling.

• Click on Programs → Chess.
  
• Surround the red ball with chess pieces to make it move in any direction.

• Bring the ball to the hole to finish the task.

• Build this pyramid using the now scattered bottom icons. [1]
  
• The following completion screen will show up. [2]
  
• Click on the switch to to shift the gravity.
  
• Build this pyramid at the top of the screen.[3]

• Click on the last white node and solve the easy equation.

ㅤ│ Hello / 3 = 378.

• Press W after completing all puzzles.