The goal of Color 21 is to drop the colored orbs into columns to create sums of 21. Go over 21 or "bust" and the column takes damage. Damage a column 3 times and you lose it. The game ends when 5 levels are cleared or all your columns break. Bonuses are available to increase your score. Left click an available column "hole" to place the orb into that corresponding column. The game adds the numbers for you. Avoid going over 21.