"The idea of the game is to line up enough Gems of the same color in a row to earn a Drop. Use the keyboard to rotate the Gems, and move them over so that the colors line up. They can line up horizontally, vertically, or diagonally. When they line up, they clear and the Gems above them fall in their place. Now those may clear too. You will see some incredible chain reactions if you place the Gems just right. Each level has a different Threshold, which you can see at the top right of the screen. Each level also has a Not Threshold, which lets you know how many Gems to line up to earn a Not. Nots let you use special effects. These help clear Gems that are on the board. When you've earned enough Drops, you can advance to the next level. There are 100 levels in all. (Don't forget to look for the secret password.)"