Nice game! Great 3D models and nice music too. Loved the 2x time forward button. Much needed in a game jam game. Would be nice to zoom out and see the entire world at a glance but the camera movement helps anyways.
I think to add more complexity to the game perhaps different enemy types could attack different areas? Like perhaps a house could be introduced and then we could put heavy unity nearby so that they can protect that house and not have to travel far while we disperse lighter units according to the threat.
I also feel that maybe some fixed entry points for attack could be introduced? Like perhaps our world could have multiple gates and rather than seeing the spawn location of the enemies we rather hear some "rumour" that X enemies will enter from gate A and Y enemies will enter from gate B. It would then be upto us to call this a bluff or not. And that would be more engaging in my opinion.