to get 3mil fully upgrade everything and get as many nukes as possible (I had 40)
shoot the tank more forward than up when you hit top hight use the rocket once you stop going out of the screen shoot him with the golden gun repeat that until you run out of ammo start using nukes as much as possible and if you're lucky, you'll get it (don't forget to hold w and d the whole time)
you can't kill him with axes. stand on the platform right before the rope and fire axes. you should be able to hit him and he doesn't shoot back. his health regenerates to fast.
my strategy was to buy the desert eagle upgrade it a little then when I could buy the SMG upgrade that then suck it up for a few levels and go straight to the mini gun and it worked perfectly
you conquer a city by battling it once you get there
and when looking at cities, green means you can sell it there for more than you bought it and red means less
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