OOOH the easiest way to beat levels 1-10 is just to buy the bionuclear auto turret and it will take care of the first few levels, then just get a fully automatic SAM site and you can win easily
one thing makes this game very bad: When you use escape wings, what the hell are you supposed to do if you restart on floor 59 or so? you're stuck with a knife and basic defense until you get the money for more. that's bull. I just used the escape wings, and i restarted with little money and i'm screwed. So much for this game.