Campaign

Fifty levels, in six bands that each introduce one idea and then play with it: rows to learn the paddle on, gaps that march across, tough bricks that take two hits, unbreakable walls, shapes, and a finale with one fewer ball.

Every level is proved clearable before it ships. A brick is reachable when it borders space the ball can get to — and space opens up as bricks break, so the check is a fixpoint rather than a single sweep. A level with a brick walled in behind unbreakable ones cannot be built.