Aim and shoot to match three or more bubbles of the same colour. Clear the board before it reaches the bottom.
Drag anywhere on the board to aim, then release to fire the bubble from the shooter. When your bubble touches two or more bubbles of the same colour, all connected bubbles of that colour pop and disappear. Any bubbles left floating with no path back to the ceiling fall away too, for bonus points. Clear every bubble to win — but if the stack reaches the bottom line, the round ends.
Aim for the edges of colour clusters rather than the middle — popping from the side often disconnects more bubbles at once than a direct center hit. Watch for opportunities to knock out a "support" bubble that's holding up a cluster of a different colour; removing it can bring down a whole floating group for bonus points. When no obvious match is available, bank your shot off a side wall to reach an angle you couldn't hit directly.
What happens to disconnected bubbles? Any bubble no longer connected to the ceiling — directly or through a chain of neighbours — falls away automatically and scores bonus points.
Can I bounce my shot off the walls? Yes — bubbles bounce off the left and right walls, which is a useful trick for reaching awkward angles.
What ends the round? The round ends if the bubble stack reaches the bottom line near the shooter, or you win by clearing the board completely.