Check your peephole first.
: You use your accumulated gold to upgrade your door and build various fortifications, such as turrets, on the empty floor tiles of your room. How to Play on PC
: Don't build everything at once. Focus on your economic status first to ensure you have a steady flow of resources for late-game upgrades.
: No more "fat-fingering" the wrong upgrade button in the heat of a ghost attack. Better Visibility
: Sleeping generates "Gold," which serves as the primary currency for upgrades.
: Only upgrade your door when the monster is actively attacking it; otherwise, keep focusing on your economy. Strategic Milestone