This is decidedly beautiful. Love the fluidness, love the colors even more.
Regarding the black frame, I do think it looks better without it in a non-contextual kinda sense, like this. But in a game, the black frame definitely helps, especially if you can sync it to a good explosion sound. You know the first syllable in "ker-POW"? That's the black frame. No explosion ever has a pre-bang like that in real life, but a good explosion in a game probably ends up having it. Some games even give weapons the same effect (which bugs me, because it rarely works (See the pistol in FarCry PC)).
Anyway, beautiful.