How Game Pausing Works in Godot

Pausing a game in Godot involves more than just "freezing time"—it requires telling the engine which parts of your game should stop and which parts need to keep running (like your pause menu buttons!).

The Global Pause State: Setting get_tree().paused = true freezes the entire scene tree. By default, this halts all script processing (_process and _physics_process), physics calculations, and input handling for everything in the game world.
Process Mode: Every node has a Process Mode property in its Inspector. By default, most nodes are set to Inherit (meaning they pause when the tree pauses). However, if your pause menu or UI buttons are set to pause along with the game, the player won't be able to click "Resume"! To fix this, you change your menu container's Process Mode to Always, telling Godot: "Keep running this node even when the rest of the game is frozen."

It Fires Once Per Press: _process() runs 60+ times a second. If you checked for the pause key inside _process(), holding the escape key down for even a fraction of a second would cause the game to frantically stutter-toggle between paused and unpaused dozens of times. _input() only triggers once the exact moment the hardware key is pressed.
Handling the "Frozen Tree" State: When you pause the game (get_tree().paused = true), standard _process() functions stop running entirely for nodes with "Inherited" process mode. To unpause your game, something must still be listening for input while the game is frozen. A node managing the pause menu set to Process Mode: Always can still capture events via _input() to toggle the game back to normal.