I found a bug when you go to get all in the port it leaves a little left over of energy. I'm not sure if it is just me or what. Upvote if you've seen it too so that dev can fix this issue
I think you need
1) a larger skill tree, like things cost less mana, either initial placement or upgrades.
2) different difficulty levels
3) be able to make taller towers/barracks (don't know if that occurs later in the game, only about halfway through)
lol, I hope in a good way. Don't worry, that door isn't a "hatch"