Some difficulties figuring out the UI
Various details of the UI left me confused for a while. These aren't exactly bugs in the game, but they did make it hard for me to move from Gal Civ III to here.
Ship designer:
Under the design / equip mode choices, if the mode is design there are exactly two icons, one for hull, and one for parts. Since they exactly line up under the design / equip items, I thought they were icons for those two items. It took me a long time to figure out to click on equip.
I didn't realize that parts would be automatically mirrored on both sides. I kept trying to rotate the ship so I could see the other side.
I still don't understand the three different colored shrink/stretch handles. They all do the same thing for me. I assume that is because all scaling for all three axes is locked for me, somehow, but I haven't noticed how to change that.
I haven't found an indication of the remaining weight capacity of a ship, or of the weight costs of equipment. I have ended up just trying and seeing when I can't add any more.
I haven't found any way to alter color or other surface properties.
Other issues:
It took me a long time to find the command to upgrade a ship. Starbases seem much more intuitive.
I haven't found a way to find out how many citizens a base plant has, except by clicking on it.