I couldn't believe when someone told me this stupidly simple trick so i've tried it with the "There is no Spoon" Achievement.
As you can see below, the Save isn't tainted when a Mod was enabled and so i've earned one of the hardest Achievements in the game by doing literally 5 mins of work and playing around a bit before i disabled the Mod and reloaded the game. This is a bit disappointing because my so called Achievements aren't worth anything. At least it feels like that.
Steam Achievement unlocked
![Sad :(](./images/smilies/icon_e_sad.gif)
Ingame Achievement unlocked after ~33 Minutes
Please fix that. I feel empty now and i don't know what to do next :[