Loved this game! Very smooth gameplay experience all around, I can tell that you made use of that playtesting really well. The aesthetic is simple and pleasing, the animations of the paddles are extremely satisfying, and even the ball has some nice visual touches to it. The blocks that you break are a bit dull in comparison to these cool things, but that's okay! The game was just the right level of challenge for me - enough to make me try but not get angry and give up. Decent length too! And the idea works superbly even if "level-based pong" isn't the most crazy thing out there, you've done it really well.
The ball travelling in exactly the same angle every time does detract a bit from the Pong experience. Pong usually has the ball travel at different angle depending on how high up the paddle you hit it, which adds a nice level of skill and challenge that isn't present here. Perhaps you thought the game would be too hard with that though, since again I do think you have a nice balance of difficulty in this.
Would've loved to see some more variation in the enemies! The ones that copy your movement got me really excited to see more unique behaviors, but I never really had to 'learn' an enemy other than that.
The final boss battle was A++. Seeing an awesomely-drawn figure like that after the, shall we say "chaotic" paddle designs you see before was actually a cool contrast. Once again really smooth animations here!
Some audio would really make this feel like a full package!
Great work, one of my favourite submissions so far, by far