I like Nighteye's effect too, but the point it isn't unique or strange like most Shivan things are.
Also, different metal salts produce different colored flames, as shown by that video, so there can be a differece in appearance in something as simple as a flak burst. The availability of a certain metal over another. Maybe Shivans have access to copper-rich (for green) or strontium-rich (for red) salts for their explosives or something, where as T/V only have access to the standard fare?
Color you can always justify like that.
Now if the Shivans have energy flak (not going to try to think of how - it's SCIENCE!), then that would explain something that doesn't even remotely look like an explosion.
Also: Rule of Cool.
EDIT: Yeah. Color, regardless if they're both energy flak or both not energy flak.