You are not using transparencies right?
Nope, I don't use transparencies. Do you ask this because those are performence killers too maybe?
No, I guess they are not, but I saw in another thread you wanted 3d explosions. That is the reason.
While I was thinking about it, I got to a´what would the art style be' situation, and transparencies make a lot of differences, either on or off.
3d explosions with transparencies are ´more or less´ an easy thing.
If no-transparecies, then it gets harder, these are what came to my mind: (beware the dreaded text wall!

)
My first thoughts about such was doing something similar to FRONTIER on the amiga, quite a nice inspiration but they are vectors instead of 3d(ye the balls).
My better second thought was about doing a voxel explosion but with polygons.
Mind polygonised voxels do have a resolution limit depending on number of cubes and your final screen size and art style, they also animate on a 2d fashion, so the may ´jump´ if not having enough frames/objects.
Textures can help easy that up, so as smoothing polygons like fluids.
Because of Ian Price´s Aquaventura game, where when you collect a diamond you see a nice blinking animation made with well positioned pixels, I got a hype to research pixel special effects for my own game.(super thanks Ian

)
While at that, I learned some interesting 2d stuff, and I applied a couple to my game.
An interesting thing on one effect, was that it was actually based on a 3d projection (the one jpg appended).
Like I had to draw splines on photoshop but had to consider a 3d space while doing 2d (is it understandable?).
At the same time, I have been marveled by the 2d art in KOF XIII, and I always suspected that there was some 3d going on there as a sketch (an atempt to de-construct things I like), specially for cloths and shadows. A couple days ago I saw a doc about it, and while the director stated they did it all on 2d, at some point he sneezes that everything was first done in 3d to get perspective right and bla bla... gotcha!

So these 6 things got together in my mind in no particular order:
1- Ians ability do draw 2d anim fx in a cool way.
2- De-constructing kof XIII art technique.
3- how to 3d explode things without transparencies.
4- Voxel to 3d conversion program made by Scott_AW.
5- my own game effect sprites after researching that subject.
6- your game.
Oh well, not to drive this off topic answer to much,
I´m now interested in doing an experiment explosion in 3d by voxels to cubes.
I´m appending my current 2d explosion(in jpg) I´m using on my game so you get an idea (the elipse/circle one).
The ray is easy to 3d draw, the smoke ellipses are a bit harder to do on sliced images editing.
Animating them without a prime visualization is even harder.
If the results come up any good, I send you the 3d cubes/voxel version and if you like it, you are free to use it (if Scott_AW is ok with it too

as I´m thinking of using his tool instead of standard 3d packages)
EDIT: I will see to do a 32x32 voxel/obj instead...gotta keep the flat low poly going
EDIT2: actually I will try lower for the same reason/style.