Wow loved this. I was able to complete it on my third/fourth run. It had a bit of a learning curve to it. I didn't know how useful leech was until I played Alchemist and it ricocheted :) Then I achieved god-like immortality. (might need nerfing or not)
I got into an incident when one of the characters got shot outside the map. I combined the homing modifier and the ice bomb, which shot the little guy out of the map. I was able to kill it after a while of guessing. Maybe the map has some extra space there. I didn't know when it died so I was thinking having an enemy counter would also be a nice addition. 
- Your friendly cat in a box