First you need to complete whole game. To completing that fastest do the following steps:
1. Click "New Game"
2. Press letter "L" 50 times
3. When you get to the level 50 press following buttons in that order:

Up x10
Right
Up
Right
Up

Left
Down x2
Left
Down
Up x3

Right
Left x2
Down
Left x2
Down

Up x9
Down
Right
Down x5
Right x2

Down
Up x4
Down
Left x2
Up x6

Right
Left x4
Down x4
Right x7
Up x3

Left x7
Down x3
Right x5
Down
Up

Right
Upx2
Right
Left x7
Down

Right x5
Up x3

After you complete the first step do the following steps:
1. Exit the game
2. Open Steam library-> Right click on the GooCubelets: The Void->Properties->Local Files->Browse Local Files

3. Open GooCubelets The Void_Data
4. Download this link [drive.google.com] (On that link are all that replaced level files) or do it by your own like this:

Delete all level files from level 6 to level 54 and after that make 49 copies of level 5 and rename them into level 6 to level 54

This will replace all levels with level 1.

I suggest to use some automation (script) to unlock these Completionist achievements while you are busy with some other things. Do it like the following steps:
1. Download Script Program from the official site [www.autoitscript.com].
2. Download Script file link [drive.google.com] or do it by your own like this:
You need to create text file with au3 extension and paste the following text into it:

WinActivate("GooCubelets: The Void")
AutoItSetOption("SendKeyDelay", 200)
Local $counter = 0
Do
Send("{LEFT 2}");
Sleep(250)
Send("{LEFT}");
Sleep(250)
Send("{DOWN 2}");
Send("{LEFT 2}");
Sleep(250)
Send("{UP}");
Sleep(250)
Send("{UP}");
Sleep(250)
Send("{LEFT 2}");
Send("{UP 2}");
Sleep(250)
Send("{RIGHT}");
Sleep(250)
Send("{RIGHT}");
$counter = $counter + 1
Sleep(4500)
Until $counter = 375

If you download a script file just right click on it and click Edit Script to make sure the text is in.
This should look like this:

3. Open the game. (On windowed)
[You can try complete the level 1 manually to make sure that the next level is again the same level, if there is not that, that means you failed 2nd Step]
4. Make sure the box is on the start position. [Don't close the game]

5. Run Script [Right click on the Script file and click Run Script]

There is other option to run the script and that is this:
1. Open AutoIt3 files location [mine is here: C:\Program Files (x86)\AutoIt3]
2. Open the Application (_x64 if you have 64-bit)
3. Find Script file and Open it

That's all!

Script will select the game window and will repeat completion of the first level more and more times.
Please do not use PC while script is working.

If you need to interrupt it - please look at system tray. The AutoIt Script icon should be in notification area. Just right click and select "Exit".
The one iteration took about 10 seconds, so it will require about 63 minutes to unlock all achievements.

Thank you for reading this guide!

This is my first real guide and I wanted to make it look as great as possible.
Hope that my solution will help you to get all these achievements.
The script may be not optimal - it was my first experience with AutoIt utility.

Special thanks to:
Yurick - Because he told me for that script.
Check his guide here:
http://cs2bus.com/sharedfiles/filedetails/?id=938231902
Intelligence - Because he told me for replacing level files.
Check his guide here:
http://cs2bus.com/sharedfiles/filedetails/?id=937125694
F&F - For his Regular Achievements Guide.
Check his guide here:
http://cs2bus.com/sharedfiles/filedetails/?id=837359802