FYI, if you're in CS4, Linkage can be found by selecting "Properties" when you right click on Explosion and then clicking the Advanced button. (Basically it's a direct way to set up the options you usually do when you create a new symbol)
A lot of fun, but unless you figure out a good balance of what to use, you'll be at the computer for a while gaining a few pixels here and there and getting a few cheap shots into their base. Do-able, but takes a while that way.