Really cool game. I like the 1bit style and how good it is polished, especially for a first try.
If you want some constructive feedback, it would've felt less passive with a minimalistic control over your army. Just calling them back and pointing to a specific target. Or scrap Auto-Aim of the mage for a TopDownShooter control.
But that said. I really like it.
Was looking for some summoner games inspiration, because I'm planning to do one myself and yours gave me some inspirations^^