Great game! A lot of fun! I'm a little sad its so short, but the ideas and mechanics seem really thought out and polished.
One thing I think might be nice to have (but not at all necessary) is some indication of how each unit behaves on the battlefield. I.E. "This unit attacks enemy with lowest health" or "this unit attacks closest enemy", etc. This could add a strategic element at the start when placing units on the field.