That's such a lazy title isn't it ( I bet I've used it before )
Ok adding the Game Over stuff may not seem such a big deal, but it's an essential part of the flow. It's almost a complete ( Rather than finished ) game now, we only need the game complete sequence, which I've not really thought about yet, and that'll be it, the flow from start to finish, which is a great milestone to get out of the way.
The other part of doing the Game Over sequence is that it's a way to test that all your house keeping routines are working, that sprites and particles are being properly killed and put back into their pools etc. I know that happens between levels, but it's still important that the game can transition from title screen > game > title screen again with nothing breaking and everything nice and clean.
You'll notice the blurred baddies. I did try Starlings blur filter in a vain hope that may just be powerful enough, but it gave me 20fps on desktop, and as I keep the level playing in the background it just wasn't going to work. I did find a good looking alternative on the Starling forums ( http://forum.starling-framework.org/topic/code-much-faster-gaussian-blur-implementation ) but by that stage I realised it just wasn't going to be practical to perform a real time blur on a ton of objects.
So I cheated, and just exported all the baddie sprites and bullets with a blur, and adding them to the sprite sheet. We're doing fine in terms of GPU memory, so although it's a little extravagant we're no where near to hitting any hardware boundaries.
That's it, game over man.