I really like the mechanic of picking up your dead enemies and creating some franken-tank. I also liked how the arena walls were dynamic. I would suggest changing the camera angle to be a bit more top down (might require a slight zoom out to compensate) since it was a bit hard to see below me if I was on the top half of the arena.
My favorite part though is when you think you're unkillable because you have so many tanks strapped to you and then the boss comes with an equally ridiculous amount of tanks strapped to it.