Hi Simon, enjoyed this, nice take on Block Breaker. Sound effects are nice, cracking is subtle, ball bounce is fun. Background graphics are also fun and suit the type of game.
The music I found got a bit annoying, the clip being used repeats pretty quickly and levels on this type of game can take quite a while sometimes to complete - could just be me though 
I saw you have gravity enabled for the ball, I’ve seen this used quite a lot of times and I’m not personally sure that it should be there. If you get a rebound which sends the ball almost horizontal it looks quite odd in my opinion that the ball just falls back downwards… again, might just be me from all those years on Arkanoid on the Atari ST…
When you make the game go full screen on itch.io the “Lives” counter looks like it’s been moved under the bricks. Only saw it once and did have chance to really give it much thought. You’ve already mentioned it in your original post obviously.
Last thing I noticed was that if you let all your lives go (e.g. just fail to hit the ball) - you can see that before you goto the game over screen “lives” jumps back to 3 again 
Really like the idea of the level selection at the beginning, very cool 