Actually, if your aggressive you can beat it without getting any system upgrades. All I did was get armor and attack upgrades and took out the first base fairly early. I was planning to get some new systems after the second base but then we won

. I did invest in two small armors but that was it, we had no problem holding them back without systems... didn't even lose any of the overmind defendrs...which btw if there called defenders should maybe kill something every once in a while. There more like fodder at the moment.
Anyway, I am glad to hear that a more final version with more options is near done :-)

!!