The goal of Cosmic Drop is to race your circular ships to the planet surface, each level gets a little bit more difficult. A single surviving ship is enough to progress to the next level.
Touch and drag comets that have touched your ships out of the path of your ships. Comets with flashing colors indicate they can be dragged, other (non-touched) comets can not be moved. Use the flashing comets to destroy enemy ships, a fast swipe may destroy more than one enemy or use the comets to shield your ships. The more comets and enemies you destroy the higher your score.