One ball rolls into x1 to x5 multiplier gates and comes back as many, wave after wave, until hundreds of balls smash a pane of glass.
Glass Rush asks one question: can the ball multiply fast enough to break the glass? A single ball drops in at the side of a round arena, rides the entry lane round the bottom and up the far wall, and a kicker knocks it into the middle. The lower half holds nested U-shaped lanes and a bowl, and at the floor of each one sits a multiplier gate: x5 in the bowl, then x4, x3, x2 and x1 outward.
A ball that reaches a gate pops, and that many balls drop in with the next wave. Each wave is launched a little harder, so the first lands in x1, the next in x2 and so on, and the crowd grows from one ball to hundreds in a few waves.
Once the waves fly past the last lane they start landing on the glass at the top of the arena. The glass breaks away in ragged plates with cracks spreading round the hole, and a ball that breaks glass goes with it. When only a little glass is left, the rest shatters in one wave and the round starts again.