A few things

Make child entites work.

z-sort entity list before rendering.

entites have a creation timestamp.

include/Engine/Entity/Camera.h

@@ -9,5 +9,5 @@ class Engine::Camera : public Renderable {
 public:
     void Render() override {};
 public:
-    explicit Camera(const Vector2& position) : Renderable(position) {}
+    explicit Camera(const Vector2& position) : Renderable(position, 0) {}
 };