Never thought I would have so much fun playing flash game. You proved me that flash games can be. Great innovative game you developed. I would give you more stars if I could. This game definitely has replay value in it. Port it to the PSP!
Buy five .50 cals first, upgrade soldiers with BAR machineguns, if you lose .50 cals, replace only up to 2. If all are still alive by wave 35. Add more .50 cals, or medics to support your soldiers. Start picking up crates at wave 14 or earlier if they are dropped close to enemy spawn line. Place your units in a checkerboard manner so incoming explosives and air attacks dont wipe out a group of units. Try to find an empty map because trees and other obstacles hinder gunfire and line of sight for your soldiers. Remember to have only up to 11 units until Wave 50, dead or alive. Good luck!