Took a crack at your explosion.
Some pretty sketchy fixes, but two big things:
you dwelled too long on the biggest part of the explosion, and you didn't have any darker smoke!
A list of what I did:
-tweaked the animation timing so it had a slight delay on the initial spark, to give the rest more of a POP. Also removed a frame of the larger part of the explosion.
-Added dark internal smoke.
-tweaked the last two frames to have more of a consistent line of motion between the dissipating smoke, it's not always applicable with explosions but try to stick to good clusters and tufts rather than individual pixels
-added a "shinespark" to it (that long pixel) to emulate lens flare.
-added some yellow "brights" to indicate plumes of fire lighting up the smoke from inside.