Good game! Very addictive, but not easy. I did a lot of runs but was not able to finish it.
The controls are good. A minor thing you could improve: It makes no sense to have two hexes moving to each other, would be nice if a move command from hex A->B would remove a move command from B->A.
Regarding the Hex upgrades: I mainly used the increased production. The attack and defend upgrades are difficult to use. They are often only useful for a short time...
Overall very well done!