Algodoo

Looks good. Maybe you can make the explosion fade with time. I used the following script in my Death Ray scene:

Scene.addCircle({
drawBorder := false;
drawCake := false;
collideSet := 0;
pos := e.pos;
radius := 0.5;
airfrictionmult := {0.1 + (((sim.time - controlleracc)) * 4.9)};
controlleracc := sim.time;
density := {sim.time > controlleracc + 1 ? 0 : 0.005};
color := {[0.5 - ((sim.time - controlleracc) / 4), 0.5 - ((sim.time - controlleracc) / 4), 0.5 - ((sim.time - controlleracc) / 4), 0.5 - ((sim.time - controlleracc) / 2)]}
});

This code was adapted from Smoke by Gear97.