Very interesting entry. Figuring out how to play was a bit hard at the beginning, but nothing to worry of.
I liked the art, the gameplay was fun and some levels are quite challenging. (I died on stage 2, stage 4 was actually pretty easy imo).
Also, I feel like the first units was a bit too powerfull. I ended up using only them cause they are cheaper and strong enough to overwhelm the enemy and beat the game without too much effort.
Anyway, very nice job, take care !