To make it more challenging for me, I've been playing to cap all five emitters, starting with two mortars and three blasters, and then adding one blaster for each of the first two emitters capped. Drones are not allowed. Not every map is a challenge that way, but some sure are.
I absolutely cannot get past Challenge Level 12. I have followed both the walkthrough and the youtube video on it exactly, and I can't seem to do as much damage, eventhough I've leveled up 5/5 on everything in use on that level. I need help! It's my last challenge level, and it's beginning to challenge my sanity!