A few things

Make child entites work.

z-sort entity list before rendering.

entites have a creation timestamp.

include/Game/Entity/Box.h

@@ -12,5 +12,5 @@ public:
     void Render() final;
     void Update() final;
 public:
-    explicit Box(const Vector2& position, float rotation = 0.0f) : Renderable(position, rotation) {}
+    explicit Box(const Vector2& position, unsigned int depth = 0, float rotation = 0.0f) : Renderable(position, depth, rotation) {}
 };