I’m interested in trying out 100%, how do you reset the collectables back to 0? I can’t find an option for it in game.

To delete your save data, go to C:/users/[USER]/AppData/LocalLow/Back to the Feature/Invertigo/76561198219521551 and delete 'save_full_game'.

Awesome, thank you! :)

Update: a button to clear all progress has now been added to the options menu!