If your achievements broken in steam

if you not get all achievements or want reset achievements you can remove your saves here:
YOUR_STEAM_FOLDER\steamapps\common\A Game About Digging A Hole\DiggingGame\Saved
Remove SaveGames folder and you reset game progress. Backup your save if you want to roll back your game state.

To get to achevements mode after reset you should finish game once.

If you wan't just play in achievement mode you can use this save to get to achievement mode directly:
https://drive.google.com/file/d/11CdSNpHXVRniKv6Mye2lbngTP8QklLtz/view
Just unplack it in:
YOUR_STEAM_FOLDER\steamapps\common\A Game About Digging A Hole\DiggingGame\Saved