Great game. One tweak I'd suggest: If the Guided Missile System is so smart, it really ought to refrain from firing on the odd occasion there's no target...
Ended up skipping the penultimate level because it was basically impossible...anything I built just died immediately. Started the final level, had 3000 points right off, surrendered immediately, went back to my armoury for The Annihilator, restarted Final and built an Annihilator Stardock straight off. Once I had a couple of repair turrets (just in case) and built a few Physics Labs, Annihilators were swarming like Miners. Marvellous.
Nice game. Couple of times managed to "win" when my life ran out EXACTLY on the last enemy of a stage. And the fact you can't actually field the Chinchillas in battle is a tragedy...
I also went in the wrong door (and am now stuck in the room with the orange/light-orange shield) . Slightly annoying that it's possible to get stuck in a room that provides no key.