Thanks! Yeah really decided to go for a very simple game so I'd have loads of time for polish.
What do you mean by getting stuck? Actually stuck somehow or just the ball bouncing around somewhere in the middle? The key to scoring well is the latter (and maintaining it too as it just keeps increasing the multiplier). The spin was really only added just to make getting stuck harder. Not sure if impossible though, still can at least jam the ball with the paddle so it gets stuck between the paddle and wall. And another use was to still have some form of control when the ball was doing its bouncing stuff. So kinda like slams in pinballs without the annoying tilt functionality.
The numbers are really very simple but of course they aren't that obvious to notice. When you hit a block, the number increases and it will expand to one of the four available directions. I run a collision check for all four directions and then pick one of the unoccupied ones. And if there isn't a free option, the block will break. And when a block breaks, it leaves around a "ghost block" for a a short duration which blocks other blocks from appearing at that same spot immediately. This made the game less prone to go fully solo mode for too long periods of time.