The Zapper achievement can easily be missed and would require you to replay the whole game in order to get the achievement.

OR you can simply download the save file I backed up

If you want to download and use my save file follow these steps:

1) Download the save file I'm hosting on googledrive here : https://drive.google.com/file/d/1RcdNl01F-DL8Z5d7vvBfWSVaWtBgYsme/view?usp=sharing
NOTE the game only handles 1 save file so back up your own one if you want to continue on with that save after doing this

2) Open the following directory on your computer, and replace your save file with the one downloaded through the link above.

Windows :
C:\Users\YOURUSERNAMEHERE\AppData\Local\MoonsOfMadness\Saved\SaveGames

Linux / Proton :
~/.local/share/Steam/steamapps/compatdata/1012840/pfx/drive_c/users/steamuser/AppData/Local/MoonsOfMadness/Saved/SaveGames/

NOTE if you can't see the AppData folder then you have it hidden on your computer, depending on your operating system the way to change this differs, so google your operating system (for example windows 10) and how to unhide AppData.

Once you have loaded the save file simply walk to the flooded part of the basement and electrocute yourself by walking into the water.