Love the concept. And the aesthethics are wonderful! How the paddle 'merges' with the walls or the trail the balls make ... lovely!
The gameplay is nice, but like mentioned before, the balls have some unpredictable behavior. When I just shoot them back straight, they will sometimes twirl upwards to the ceiling and I have to wait until they slowly get back to my paddles.
But overall great submision! So simple, but also so nice!