Good game. Loved the whole look of it. Looks similar to 'Bad North' for me, which is a good thing.
I have some suggestions, if you don't mind:
- I got a feeling that the enemies always go through one path only, so you can just defend that one particular path. Maybe you should add some alternative routes or other goals for the enemy (like other buildings);
- Considering the point above, letting the player to move units during the battle would be nice;
- The rewind itself is not that useful in the battle. I mean you use it once and then it is just auto-battle. Would be great if you could rewind any time (or multiple times with a cooldown or just some number of times) during the battle, so you could make strategical choices more than once per battle.
Also I had a bug, when the enemies got stuck near the ship (https://ibb.co/3YL1F22).
Overall, I liked this game, I think it has potential. Looking forward for further improvements.