HUD animation with game in background

Hello,

I want to create a transition where objects (e.g. cubes) fall from the top of the screen to the bottom of the screen. (meanwhile a deathscreen gets visible)
This transition needs to be animated I guess, but I don't know how I can play the animation like in front of everything, so that the game is visible behind this animation.


So actually what I need is:
- the game (3D) in the background
- the deathscreen in front of the game
- the animation in front of the deathscreen

How can I achieve this?