I'm coming at this with intent on open dialogue for what you want out of this game, and if you'll move onto something else, or continue developing the game you made here.
- When I saw 6 slots for the army I expected 9 allies to place in army.
- That may be to much so allow 4 slots.
- Each ally with a critical role, to killing waves.
- A way to add tactful actions to the game.
- Managing what soldier is brought into battle and the advantages they bring to certain enemies.
Truth being, I don't know how to make your game better.
I will tell you that I enjoyed when the archer died uncovering the swordsman and spearman to both attack and be attacked. (I placed archer in front, and grunts in the back.) The excitement was uncovering something new about YOUR game.
If YOU want follow up on this concept for a game, join another one month game jam. If this was your first time making a game like this, you'll likely see that you have a lot more time to actually think about how the game operates with the player.