I can't tell from the still frame if anything special is going on with the light. At first glance I thought it was just nicely colored sprites, and alpha. Though it looks like there might be some additive blending(one of the built-in effects), saturation, or a tiny bit of bloom(CC bloom effect by Davioware, here) on that blueish sky back there.
if those boxes at the bottom are bumpmapped or something I can't tell without video either.
Do you have a link to a video, or the game title?