at first i want to say is that this Game is very unique and has an awesome Style. You made a very nice game.
The Sound is very relaxing and determining. The Background music is just nice.
But sometimes i miss a more faster/busier sound, for example when there is a Battle with about 100 units.
These Situations should feel a bit more epic.
In the moment it's just like: "Yeah. I just smashed 3 asteroids with 200 units."
and with a little more dramatic music it would sound like: "EEEKH my armada is pwning tem to bits!!"
Otherwise i dont like the shoot sound of the units.
I hope you see what i mean.