Thanks for the feedback!
There's a known issue where if a node (the larger circles) have a radius too large then it becomes nearly impossible to capture, because attackers don't recognize it as path-able. Our path-finding and enemy AI code was entirely hand-written. In the end, just those two things took about 30-40 hours and are about 2000 lines of code. As such, there was a lot of polishing and bug-fixing left to do.