Thanks to the post viewtopic.php?f=5&t=29709.
So, first of all, I want to explain how disabling achievements works in this game:
- Create new freeplay game
- Run a console command
- Get your achievements disabled (profit, lel)
- Load you game and say something in the game (using `), for instance, "achievements_plz"
- Copy your save file and extract it form zip archive
- Find file called "level.dat" and open it in Hex editor (Notepad++ plugin will do the trick just fine)
- Search in ascii mode for exact thing that you typed in the game ("achievements_plz" in the example)
- Find and set desired bit to 0
- Save, add to zip archive, profit