This is not so much a suggestion as just me thinking out loud.
In Gemcraft (one of my favorite games), there are different color monsters and different color gems. If you combine gems in various ways they have different effects.
How would it be if there were different color creeper and one could put lenses in front of the blasters to modify the light emitted? Only certain types of light will affect certain hues of creeper?
Totally different game, I know, so just musing.
That sounds . . . . interesting . . . . . . . LAZER LIGHT SHOW!!! WOOT!!!
Ya but anyway, this would be fun, though I dont either of us knows just how hard it might be to implement such a thing