I think the enemies could be developed more. I was easily able to shoot the earth ones even when I was close and they wouldn't aggro or move torwards me. You can also bait the earth and wind enemies into weird spots, where they'd try to go through walls, and get stuck, allowing me to get easy kills. The wind enemy can also charge at you from off-screen.
The art is great and the spinning attack is unique and intuitive, I think this game could benefit from having more enemies per wave. Overall good game!