I didn't read the controls before I started playing - my bad lol So I just ended up kiting Barnie with the mage and beat him with just the normal attack.
I'd love more UI elements - add images with the attacks and cooldowns if applicable (when can I use "E" again?) and more feedback on when I get hurt (my melee units just got wasted because they bumped Barnie's toes). Overall, though, it was fun! Jazzy music, fun visuals.