Sweet.
Only crits are that it seems a little monochromatic and too smooth; I mean that there is no beginning blast at the beginning but rather it "grows" from the center
Explosion smoke becomes a bit desaturated or darker before it dies. Still you have same bright pixels during all frames.
If it is smoke try cahnge last few frames, and if it's explosion make it even slightly brighter at start and fade to the dark pixels at the end of animation.
BOOOOOOOOOOOOOM!