Glad you liked it! Guess nightmare mode isn't hard enough yet xD
Enemies starting as support units is definitely a hindrance for them; May need to disallow them from picking support factories as their first unit.
With the defend mode, initially, people would right click to move defending units, then be confused that they're chasing enemies, not going to the exact selected location, etc, because when they right click, they just expect units to move there, they don't realize they're still on "defend" mode. So that was just a thing to try and keep it intuitive.
The supply unit pathing is definitely.. questionable. It's definitely not great, though I've tried my best to remedy it. The AI in general needs a bit of a brush up for sure.
Repair beam and turret may be a little bit overtuned; With both, I'm planning on adding the ability to change the strength in a menu, where higher strength increases the resource drain exponentially, and have the current strength of the two be more expensive, with a more reasonable option at the current resource drain. Should help, I feel.
And I definitely hear ya on the support mode, that's a major thing for sure.
Been working on a lot of good stuff for the next update in general; Encyclopedia for seeing all the exact stats of units, better control of unit selection, like being able to select all of your units at once, or all of one type of unit. Plus lots of major enemy AI improvements, to make them a little more formidable; Looking into some proper neural network based enemy AI, we'll see where that goes.
Glad to hear you like it! I'll keep workin at it ^^