Drop! is a puzzle game similar to Tetris. Marbles (known as "Drops") are continually, um, dropping from the top of the screen, and the player controls a "switch frame" which can horizontally switch the position of two neighboring Drops (or switch the position of a Drop and an empty space). The player's goal is to form rows or columns that consist of three or more Drops of the same color - then the row or column will disappear and score will be increased. If the row/column consists of four or more Drops, this is referred to as a "combo" which yields more points. As the player gains score, he keeps reaching higher levels; on each levels, the Drops fall faster and the game is more difficult. Apart from this classic gameplay mode (called "Infinite mode" in the game), there's a "Tutorial" option where the player learns the rules of the game by following on-screen instructions; a "Challenge mode" which consists of 125 levels, each of which poses the player with some specific task, and completing it unlocks new challenge levels; and a "Hyper mode", where not only the screen is already partially filled and new Drops just keep coming, but also special types of Drops appear occasionally - some helpful, some harmful.