It's all right here are some useful tips:
Used the Uzi for like 70% of the game, it was insanely useful and cheap. The shotgun was not really a good choice, felt like a waste of money and didn't pack the punch i expected, didn't even bother with the sniper rifle. It really forces you to stick with 1 or 2 weapons MAX. Don't try buying every single weapon couse you will make it harder on your self. The machine gun is the ultimate for me, way better than the X-Ray, although and the X have it's uses. It's good you can switch between weapons to account for certain situations. At the start of the game always go for max money print, shit gets real fast so the more money you can cough up earlier the better - helps you keep the robot going, helps you stay alive, helps you buy guns and defences. The mines felt kinda useless tho.