A0Nasser , yes, as Aurel said, the bloom effect is a post process effect. Unfortunately there isn't an easy way to fake this. What I was able to come up with is using gradient sprites overlayed on top of the background and foreground elements (to create the misty-look effect) and an Adjustment layer on top (term loosely taken from After Effects) that ads blurs and brightness to the layers below. If the game has scrolling camera like limbo, you should fix the gradient Sprites with an every tick set position x,y, or overlay them on top of the background&foreground on layers with 0 parallax values.
I wish there was a webGL shader for that...
Bloom example
I'm putting a capx for my example, you'll need the modified radial bur effect that has some extra features and blurs a bit differently than the original radial blur. I'm posting that too.