diff --git a/docs/docs/reference/core.md b/docs/docs/reference/core.md
index 8240494..01c0f56 100644
--- a/docs/docs/reference/core.md
+++ b/docs/docs/reference/core.md
@@ -36,6 +36,11 @@ Used internally for loading, managing and unloading modules.
 Do not modify this.
 :::
 Stores the path to CORE's installation directory.
+### *Dictionary* <u>cleanup_hooks</u> = *{}*
+:::danger[Don't modify]
+Do not modify this.
+:::
+Contains a list of all registered cleanup hooks.
 ### *Dictionary* <u>custom_modules</u> = *{}*
 ### *void* <u>_ready</u>()
 :::danger[Don't modify]
@@ -96,6 +101,13 @@ Applies the a configuration.
 ### *void* <u>cleanup</u>()
 Makes sure that CORE does not leak memory on shutdown/unload. \
 Unloads all custom modules, built-in modules, frees any of CORE's classes and lastly itself.
+### *int* <u>register_cleanup_hook</u>(*Callable* <u>callable</u>)
+Registers a new cleanup hook. \
+Returns the hook id.
+### *bool* <u>unregister_cleanup_hook_by_id</u>(*int* <u>id</u>)
+Unregisters a cleanup hook by it's id.
+### *bool* <u>unregister_cleanup_hook_by_ref</u>(*Callable* <u>callable</u>)
+Unregisters a cleanup hook by it's reference.
 ### *bool* <u>is_devmode</u>()
 Returns if the framework is in development mode.
 ### *String* <u>get_format_string</u>(*String* <u>string</u>)
diff --git a/src/core.gd b/src/core.gd
index 227cdd4..8728b9f 100644
--- a/src/core.gd
+++ b/src/core.gd
@@ -57,6 +57,9 @@ var storage: CoreBaseModule
 ## Stores the path to CORE's installation directory.[br]
 ## [b]Danger: [i]Don't modify this.[/i][/b]
 var basepath: String
+## Contains a list of all registered cleanup hooks.[br]
+## [b]Danger: [i]Don't modify this.[/i][/b]
+var cleanup_hooks: Dictionary = {}
 ## Contains a list of all loaded custom modules.[br]
 ## [b]Danger: [i]Don't modify this.[/i][/b]
 var custom_modules: Dictionary = {}
@@ -223,24 +226,80 @@ func get_custom_module(module_name: String) -> CoreBaseModule:
 		return null
 	return custom_modules[module_name]
 
-# +++ etc ++
+# +++ cleanup ++
 ## Makes sure that CORE does not leak memory on shutdown/unload.[br]
-## Unloads all custom modules, built-in modules, frees any of CORE's classes and lastly itself.
+## Unloads all custom modules, built-in modules, frees any of CORE's classes and lastly itself.[br]
+## Only call this function if you're sure that your application or game no longer uses the CORE Framework.
 func cleanup() -> void:
 	loggeri.info("Cleaning up")
+	loggeri.verb("Calling cleanup hooks")
+	for hook in cleanup_hooks:
+		if !cleanup_hooks[hook].is_valid():
+			loggeri.error("Cleanup hook #" + str(hook) + " is invalid")
+		else:
+			loggeri.diag("Calling cleanup hook #" + str(hook))
+			await cleanup_hooks[hook].call()
+	loggeri.verb("Unregistering custom modules")
 	for module in custom_modules_node.get_children(): await unregister_custom_module(module.name)
+	loggeri.verb("Removing custom module support")
 	remove_child(custom_modules_node)
 	custom_modules_node.queue_free()
+	loggeri.verb("Unloading built-in modules")
 	var modules_reverse: Array[String] = modules.duplicate()
 	modules_reverse.reverse()
 	for module in modules_reverse:
 		await get(module)._cleanup()
-		get(module).loggeri.queue_free()
 		get(module).queue_free()
+	print("Freeing configuration")
 	config.queue_free()
 	await get_tree().process_frame
+	print("Freeing")
 	queue_free()
 
+# Generates a new cleanup hook id
+func _generate_hook_id() -> int:
+	var id = randi()
+	if cleanup_hooks.has(id):
+		loggeri.warn("New cleanup hook id #" + str(id) + " is already taken")
+		return _generate_hook_id()
+	elif id == -1:
+		loggeri.warn("Invalid cleanup hook id '-1'")
+		return _generate_hook_id()
+	return id
+
+## Registers a new cleanup hook.[br]
+## Returns the hook id.
+func register_cleanup_hook(callable: Callable) -> int:
+	if !callable.is_valid():
+		loggeri.error("Could not add cleanup hook: Callable is not valid")
+		return -1
+	
+	var id: int = _generate_hook_id()
+	loggeri.verb("Adding new cleanup hook #" + str(id))
+	cleanup_hooks.merge({ id: callable })
+	return id
+
+## Unregisters a cleanup hook by it's id.
+func unregister_cleanup_hook_by_id(id: int) -> bool:
+	if !cleanup_hooks.has(id):
+		loggeri.error("Could not remove cleanup hook (id): Hook #" + str(id) + " does not exist")
+		return false
+	loggeri.verb("Removed cleanup hook #" + str(id) + " (id)")
+	cleanup_hooks.erase(id)
+	return true
+
+## Unregisters a cleanup hook by it's reference.
+func unregister_cleanup_hook_by_ref(callable: Callable) -> bool:
+	var id: Variant = cleanup_hooks.find_key(callable)
+	if id == null:
+		loggeri.error("Could not remove cleanup hook (ref): Could not find a matching hook")
+		return false
+	if typeof(id) != TYPE_INT: await loggeri.crash("Could not remove cleanup hook (ref): find_key did not return an integer (returned '" + str(id) + "')")
+	loggeri.verb("Removed cleanup hook #" + str(id) + " (ref)")
+	cleanup_hooks.erase(id)
+	return true
+
+# +++ etc +++
 ## Returns if the framework is in development mode.
 func is_devmode() -> bool:
 	return config.development