EA Staff (Retired)
Infantry counter Jumpjet's, extremely hard. Once you've defended your harvester push to take the platforms and position your infantry in a way so that when he tries to dash past the jumpjets will lose half their health and keep one infantry near the harvester if any manage to get by. Jumpjets are a squad unit, this means as they lose health, they lose damage. If you kill two of them in the squad they just lost 50% of their damage potential.
I don't know how you think they're winning the battle, if it takes them 2 jumpjets to finally kill your harvester, they didn't get ahead since they spent 100 to gain 100, they simply managed to recover from their failed/overcommitted rush. If their rush is failing, you should be focusing on making sure their economy stays shut down by getting a tank out for the sole purpose of targeting their harvester if they try to build one.
