Good news for everyone who stuck with "ungiveable" those three "building/refilling/harvesting" side missions, who wants to get an Completionist Achievement and do not want to do a whole run again due to silly prerequisits.

I got it today after same stuck situation and messing a couple of hours. So, here's workaround.

Warning #1: this way require to edit save files for obtaining side missions. You may stop reading if you think that this is cheating or unfair. Steps are located inside spoiler below.

Warnings for those who are not familiar with hex files editing:

• Warning #2: this way require to editing save files in hex. Although this is pretty simple and there are a lot of guides how to do it, you may stop reading if you feel uncomfortable about this. (P.S. I used HxD, you can use it or search relevant information).
  
• Warning #3: If you are following this guide, you are doing this by your own risk. You can spoil your save information. No warranties.
  
• Warning #4: do a backup of files. After that do a backup of backup.

So, let's get started.


We are interested in Pamela's world save file. It's located in:
C:\Users\{username}\AppData\LocalLow\NVYVE Studios\PAM_GameLauncher\PAMELA_WorldSave.txt

1. 0. do a backup of PAM_GameLauncher folder
   
2. Open file PAMELA_WorldSave.txt with hex editor.
   
3. Look for 62 24 00 00 00 00 01 00 98 hex string (can't provide offset value because it is dynamic) -- screenshot #1, upper selection.
   
4. A bit after it there is a section where info about side missions is located. Seems like it's stored in bit pairs obtained-completed.
   
5. Look for 6-cells of zeros (00) in a row (if you have completed all other missions) -- screenshot #1, bottom selection.
   
6. ...or try your luck with offset from cell with "98" value from step above. My offset value is 55{hex}/85(dec) -- Screenshot #2, upper selection. My target section location -- Screenshot #1, bottom selection.
   
7. Change values of that 6-cells to chess pattern (01 00 01 00 01 00) -- Screenshot #2, bottom selection.
   
8. Save changes.
   
9. Run Pamela, you should got and be able to complete missions immediately after loading modified save.

Screenshot #1:
Screenshot #2: