Nice break-out game.
A few things:

1. The ball should start at the paddle and move away at an angle, so the player can't get free blocks by doing nothing in the beginning.
2. losing extra balls subtracts from your extra lives
3. I somehow got the ball trapped between two invincible blocks in the top-right corner like so:

Great game! One trick I've used in the past to fix the infinite loop @Verb found above is to count the bounces since the ball last hit the paddle. When it passes a threshold (say, 50 bounces,) jiggle the angle a little bit on each subsequent bounce. It's effective and largely invisible to the player.

Thanks for the feedback @Verb and @magic_chopstick, however I'm not looking to make any such changes, I'm well aware of each of those features and have all been accounted for, it is not supposed to be a carbon copy of an existing game but instead an independent heavily inspired game, the only way of getting stuck is in between a block that will grant the player power-ups and is only possible in very late game and with high precision and is therefore considered a feature, so is the loss of hearts when losing balls, as it would otherwise be to overpowered.