How to open the keyholes

the-end-is-nigh

How do I open the keyholes found in each chapter?

Keyhole in Arid Flats 12

This is the second keyhole I’ve found and I cannot figure out how to open it.

Best Answer

Could contain spoilers:

According to this question in the Steam Community, there is a master key in a later level of the game, the Machine (screen 14).