diff --git a/src/data/setting.h b/src/data/setting.h
index 1146b8ac..e25ee864 100644
--- a/src/data/setting.h
+++ b/src/data/setting.h
@@ -4,6 +4,7 @@
 #include <limits>
 #include <string>
 #include <vector>
+#include <unordered_map>
 
 #include "../typedefs.h"
 #include "../delegates.h"
@@ -30,13 +31,35 @@ public:
     virtual std::string toString() const = 0;
 };
 
+using observer_handler = std::shared_ptr<int>;
+
+template<class T>
+class Observers {
+    int nextid = 1;
+    std::unordered_map<int, consumer<T>> observers;
+public:
+    observer_handler observe(consumer<T> callback) {
+        const int id = nextid++;
+        observers.emplace(id, callback);
+        return std::shared_ptr<int>(new int(id), [this](int* id) {
+            observers.erase(*id);
+        });
+    }
+
+    void notify(T value) {
+        for (auto& entry : observers) {
+            entry.second(value);
+        }
+    }
+};
+
 class NumberSetting : public Setting {
 protected:
     number_t initial;
     number_t value;
     number_t min;
     number_t max;
-    std::vector<consumer<number_t>> consumers;
+    Observers<number_t> observers;
 public:
     NumberSetting(
         number_t value, 
@@ -63,9 +86,7 @@ public:
             return;
         }
         this->value = value;
-        for (auto& callback : consumers) {
-            callback(value);
-        }
+        observers.notify(value);
     }
 
     number_t getMin() const {
@@ -80,12 +101,12 @@ public:
         return (value - min) / (max - min);
     }
 
-    void observe(consumer<number_t> callback) {
-        consumers.push_back(callback);
+    observer_handler observe(consumer<number_t> callback) {
+        return observers.observe(callback);
     }
 
     virtual void resetToDefault() override {
-        value = initial;
+        set(initial);
     }
 
     virtual std::string toString() const override;
@@ -101,7 +122,7 @@ protected:
     integer_t value;
     integer_t min;
     integer_t max;
-    std::vector<consumer<integer_t>> consumers;
+    Observers<integer_t> observers;
 public:
     IntegerSetting(
         integer_t value, 
@@ -128,9 +149,7 @@ public:
             return;
         }
         this->value = value;
-        for (auto& callback : consumers) {
-            callback(value);
-        }
+        observers.notify(value);
     }
 
     integer_t getMin() const {
@@ -145,12 +164,12 @@ public:
         return (value - min) / (max - min);
     }
 
-    void observe(consumer<integer_t> callback) {
-        consumers.push_back(callback);
+    observer_handler observe(consumer<integer_t> callback) {
+        return observers.observe(callback);
     }
 
     virtual void resetToDefault() override {
-        value = initial;
+        set(initial);
     }
 
     virtual std::string toString() const override;
@@ -160,7 +179,7 @@ class FlagSetting : public Setting {
 protected:
     bool initial;
     bool value;
-    std::vector<consumer<bool>> consumers;
+    Observers<bool> observers;
 public:
     FlagSetting(
         bool value,
@@ -183,17 +202,15 @@ public:
             return;
         }
         this->value = value;
-        for (auto& callback : consumers) {
-            callback(value);
-        }
+        observers.notify(value);
     }
 
-    void observe(consumer<bool> callback) {
-        consumers.push_back(callback);
+    observer_handler observe(consumer<bool> callback) {
+        return observers.observe(callback);
     }
 
     virtual void resetToDefault() override {
-        value = initial;
+        set(initial);
     }
 
     virtual std::string toString() const override;
diff --git a/src/engine.cpp b/src/engine.cpp
index 3821fafa..54d62ec5 100644
--- a/src/engine.cpp
+++ b/src/engine.cpp
@@ -47,13 +47,13 @@ void addWorldGenerators() {
     WorldGenerators::addGenerator<FlatWorldGenerator>("core:flat");
 }
 
-inline void create_channel(std::string name, NumberSetting& setting) {
+inline void create_channel(Engine* engine, std::string name, NumberSetting& setting) {
     if (name != "master") {
         audio::create_channel(name);
     }
-    setting.observe([=](auto value) {
+    engine->keepAlive(setting.observe([=](auto value) {
         audio::get_channel(name)->setVolume(value*value);
-    });
+    }));
 }
 
 Engine::Engine(EngineSettings& settings, EnginePaths* paths) 
@@ -64,11 +64,11 @@ Engine::Engine(EngineSettings& settings, EnginePaths* paths)
         throw initialize_error("could not initialize window");
     }
     audio::initialize(settings.audio.enabled);
-    create_channel("master", settings.audio.volumeMaster);
-    create_channel("regular", settings.audio.volumeRegular);
-    create_channel("music", settings.audio.volumeMusic);
-    create_channel("ambient", settings.audio.volumeAmbient);
-    create_channel("ui", settings.audio.volumeUI);
+    create_channel(this, "master", settings.audio.volumeMaster);
+    create_channel(this, "regular", settings.audio.volumeRegular);
+    create_channel(this, "music", settings.audio.volumeMusic);
+    create_channel(this, "ambient", settings.audio.volumeAmbient);
+    create_channel(this, "ui", settings.audio.volumeUI);
 
     auto resdir = paths->getResources();
 
diff --git a/src/engine.h b/src/engine.h
index f4ba4878..36d61806 100644
--- a/src/engine.h
+++ b/src/engine.h
@@ -11,6 +11,7 @@
 #include "content/PacksManager.h"
 #include "files/engine_paths.h"
 #include "files/settings_io.h"
+#include "util/ObjectsKeeper.hpp"
 
 #include <filesystem>
 #include <memory>
@@ -38,7 +39,7 @@ public:
     initialize_error(const std::string& message) : std::runtime_error(message) {}
 };
 
-class Engine {
+class Engine : public util::ObjectsKeeper {
     EngineSettings& settings;
     SettingsHandler settingsHandler;
     EnginePaths* paths;
diff --git a/src/frontend/screens.cpp b/src/frontend/screens.cpp
index bd6b9dc9..63877fb1 100644
--- a/src/frontend/screens.cpp
+++ b/src/frontend/screens.cpp
@@ -86,8 +86,6 @@ void MenuScreen::draw(float delta) {
     batch->flush();
 }
 
-static bool backlight;
-
 LevelScreen::LevelScreen(Engine* engine, Level* level) : Screen(engine) {
     auto& settings = engine->getSettings();
     auto assets = engine->getAssets();
@@ -100,8 +98,12 @@ LevelScreen::LevelScreen(Engine* engine, Level* level) : Screen(engine) {
     worldRenderer = std::make_unique<WorldRenderer>(engine, frontend.get(), controller->getPlayer());
     hud = std::make_unique<Hud>(engine, frontend.get(), controller->getPlayer());
     
-
-    backlight = settings.graphics.backlight.get();
+    keepAlive(settings.graphics.backlight.observe([=](bool flag) {
+        controller->getLevel()->chunks->saveAndClear();
+    }));
+    keepAlive(settings.camera.fov.observe([=](double value) {
+        controller->getPlayer()->camera->setFov(glm::radians(value));
+    }));
 
     animator = std::make_unique<TextureAnimator>();
     animator->addAnimations(assets->getAnimations());
@@ -163,14 +165,6 @@ void LevelScreen::update(float delta) {
         camera->up
     );
 
-    // TODO: subscribe for setting change
-    EngineSettings& settings = engine->getSettings();
-    controller->getPlayer()->camera->setFov(glm::radians(settings.camera.fov.get()));
-    if (settings.graphics.backlight.get() != backlight) {
-        controller->getLevel()->chunks->saveAndClear();
-        backlight = settings.graphics.backlight.get();
-    }
-
     if (!hud->isPause()) {
         controller->getLevel()->getWorld()->updateTimers(delta);
         animator->update(delta);
diff --git a/src/frontend/screens.h b/src/frontend/screens.h
index fe0d5989..98be2ec7 100644
--- a/src/frontend/screens.h
+++ b/src/frontend/screens.h
@@ -3,6 +3,7 @@
 
 #include <memory>
 #include "../settings.h"
+#include "../util/ObjectsKeeper.hpp"
 
 class Assets;
 class Level;
@@ -16,7 +17,7 @@ class LevelController;
 class TextureAnimator;
 
 /// @brief Screen is a mainloop state
-class Screen {
+class Screen : public util::ObjectsKeeper {
 protected:
     Engine* engine;
     std::unique_ptr<Batch2D> batch;
diff --git a/src/util/ObjectsKeeper.hpp b/src/util/ObjectsKeeper.hpp
new file mode 100644
index 00000000..1791b341
--- /dev/null
+++ b/src/util/ObjectsKeeper.hpp
@@ -0,0 +1,19 @@
+#ifndef UTIL_OBJECTS_KEEPER_HPP_
+#define UTIL_OBJECTS_KEEPER_HPP_
+
+#include <vector>
+#include <memory>
+
+namespace util {
+    class ObjectsKeeper {
+        std::vector<std::shared_ptr<void>> ptrs;
+    public:
+        virtual ~ObjectsKeeper() {}
+
+        virtual void keepAlive(std::shared_ptr<void> ptr) {
+            ptrs.push_back(ptr);
+        }
+    };
+}
+
+#endif // UTIL_OBJECTS_KEEPER_HPP_