The idea of being completely at the mercy of an AI commander hoping it makes good building decisions is quite amusing to me. It just kept making more machine guns that I can't use lol.
Anyway, I think this idea has potential, but it needs a little something more to engage the player as a lot of the time you're looking in one direction holding down fire. There also isn't really much counter-play to simultaneous streams of enemies. Perhaps those both could be solved by just making the enemies way weaker and more spread out. Alternatively, maybe after exiting a gun it could continue to fire for some amount of time in the direction you were last aiming at so you could actually take advantage of the 20 machine guns your AI commander builds...
Overall though, a great looking and feeling game, good job!