How to overlay a firework show before your 2D GUI in Unity3D

You may want to have a firework show in your 2D game when your user wins. It is pretty easy with Unity3D.

Just add a new camera to your existing scene. Set "Clear Flags" to "Don't clear", and set "Depth" to a greater value than that of your 2D GUI's camera. Then what ever this camera sees will be displayed over your 2D GUI.

Then add your firework prefab as child of your new camera, and adjust its position so that it looks good in your camera. And that's it.