The kinetic converter is OP. When I installed it, not only did I get into space for the first time, I got all the way to Mars. Granted, I'd nearly made it into space already by that point, but still.
The randomization really needs to be improved. I have SO MANY GUARDS because I never get swordsmen anymore. One day, I got three - and built them each an epic weapon. Good damn day.
Goo is way too underpowered. Needs to work faster, or be larger. Could be balanced by eliminating the slow down if need be, but holy crap does it suck right now.
Coming up with the actions isn't so hard; it's the limited space in which to do them. There are so many times in the last three levels that I wished I had a third function .
It'd be nice if the guards had similar routes each time, instead of doing whatever the hell they want and making it impossible to learn from your mistakes.
Right now, I have this cop, holed up in a warehouse, who's made a nice little killzone in the heart of my class 3 outbreak. Nearly 200 kills so far, still going strong.