This achievement is still not available as of today, but I have a workaround.
 

Select the Main Menu to enable Dev Mode

If dev mode is not enabled, close the game and then restart it.
 
 
(Dev mode was broken for me. It only worked when I restarted and turned it on from the main menu. ???? What is Stress Level Zero doing?)
 
 

 
 
Click on Mods < Settings < Enable Dev Mode
 
 
 

Go to the first level and go further in to spawn Apollo

Enter 01 Descent, and continue forward until you reach a room with lockers to your left. We won't be grabbing Shiny Apollo.
 
 

 
Instead, open your menu and select DevTools. Two tools should then appear.
 
Grab the blue tool and open up your menu. Then select Utilities.
 
The category "Toy" should be in the list to the right. If it isn't, you can use the down arrow to the left until you see it.
 
Apollo will then be spawned with the tool.
 
 
 

Continue the campaign

As you go through the campaign, carry Apollo with you. These are some things you should know about this method.
 
 
After you complete Descent, the game will take your last save to the 02 Hub. It's okay, spawn Apollo once more, then go through the Quarantine doors and continue.
 
 
There are other instances when Apollo might not appear at the beginning of a level. In these cases, just spawn it again to continue.
 
 
If Apollo falls and you die, restart the mission to spawn him again.
 
 
The achievement will not unlock if you reach the end and climb up the windmill using only one hand (. However, assuming you did everything legally and carried Apollo, I would consider it unlocked. We only have one more workaround, since the devs haven’t fixed it yet.
 
 
 

Steam Achievement Manager

 
 
Search for steam achievement manager and click on the first link from Github.
 
 
Scroll down till you see "download latest release", click that, and then click and download SteamAchievementManager-7.0.25.zip
 
 
Open the file and run "SAM.Game.exe".
 
Scroll down until you find Bonelab in the list. Click it to select it
 
Click on the My Pal Apollo achievement to be taken to the next page. Next, click "Commit Changes" at top right. Congrats!
 
If you can prove that you did everything legally and carried Apollo through every level, then you are eligible to unlock this achievement. It is only fair that you use the achievement manager to fix bugs. This was only once, and that was to collect all the rings in Dark Souls 3! We will fix it if the devs don't.

 
 

 
 
This is all about BONELAB – Pal Apollo Achievement (The BS Route); I hope you enjoy reading the Guide! If you feel like we should add more information or we forget/mistake, please let us know via commenting below, and thanks! See you soon!