Fantastic stuff on display here! Overall it's a very charming game with excellent assets in all areas. But even if you're the big cheese, I do have a few complaints to make (though nothing big enough to kill it for me, haha).
I found it a bit odd that, while the main menu buttons highlight when you hover over them, the world map destination buttons were very lifeless with no highlight (they do have an animation when you click on them, sure, but I'm a strong proponent in button feedback of all sorts, especially highlights). Also, I found that the transitions between phases were very jarring, especially the transition between finishing the assembly and going to the battlefield: would love if there was a fade transition like the great gears transition on the main menu, maybe with a banner that says "Job Complete! To the Battlefield!" or something.
Finally, while I don't mind shooting the drones during the battle scene, I didn't quite like shooting the drones during the assembly scene: specifically, I didn't like how it interrupted the flow to go to a turret section. Instead, I'd much prefer if you would have to shoot stray drones during the assembly: obviously the number of drones would be less than in the turret section lest it be too difficult, but I think it would be a lot more fun to deal with as it gives you even more to juggle. Also, I wish there was a crosshair for the shooting segments, I kept easily losing my mouse during those.
At the end of the day, however, despite my nitpicks, I felt like the game did have a great level of professionalism to it, and I loved how it kept escalating with new mechanics and difficulty to contend with for each level, so nice work all!