How about also having a different troop/marine unit for
1. the aquatic planets and
2. for all others.

It always seemed kind of absurd to me that you don´t really need different equipment to capture an aquatic planet as a non-aquatic race.
And aquatic species would definitely also need some ...

I really love the artwork and the combat system so far!
Some of the things have maybe already been mentioned. I read through all the posts but by now, 4 days later I have already forgotten half of them again.
So yeah, a short FAQ might be a good idea.
Here are my suggestions:

1. Definitely some ...