The secondary missions with only AI allies sucks. Their targeting makes them go all around the map without hitting. To complete the missions, you need a lot of upgrades in these AI allies, so the gold earn is not worth it...
Hey pal, great game. I would only suggest an auto pause feature. It's really sad when you're playing in the Survival Mode an quickly try to Strafe, but instead you just click outside the window. Usually in this mode this mistake costs the match...