Yeah, for someone who hasn't played the Creeper World games, it's pretty hard to know what's going on. I think the turrets are shooting the blue stuff, if they're close enough to a power node. Maybe you're trying to beat the blue stuff back enough to take out the spawn points?
Anyway it looks beautiful, and I bet it'll be a fun game when it's finished! Hit me up on Discord and let's see if we can think of any ways to make it more efficient on the web, too.