This game gets really boring after a while.
I think for blue circles, you should get to choose whether or not you fight because, once I had all my dudes MAXed out, I wasn't getting any points for killing all the weak foes.
This is fairly easy. I just drove around in circles aimlessly until Level 14 when I intentionally flew my ship into asteroids.
If I cared about it, I could get the hard badge, no doubt.