There is no balance between $ from killing enemies and that gained for free from cash packages and gold mine. The level 42 enemy upgrade takes almost 22 Trillion to purchase and with spawn rate maxxed and 12 spawn points and lvl 34 earnings multiplier it would take OVER 10 days straight to earn enough $ from kills to buy lvl 42 enemy upgrade. For less $ I can upgrade my gold mine to earn over 1 Trillion every 15 seconds. Cash from enemies needs to be boosted over 100X to make upgrading enemies worthwhile.
 "Auto Turret"){kind=icon}