Red Minus 100. On Legendary, one red ends the run.
Blue Rare. Starts Bonus.
Yellow Bonus only. 500 points. A red ends Bonus early.
The glowing border is your 60-second clock. Clean taps play a tune and build a multiplier: x2 at 8, x3 at 16, x4 at 30. A red or an empty spot breaks the streak and restarts the tune.