You need to range planets and rockets to compose vertical, horizontal or diagonal lines of at least four similar objects so they could be destroyed.
The longer line you compose, the more points you will get for it. To move a planet, just click on it and then point its new destination.
Planets can move only in horizontal or vertical directions, not diagonal ones.
Additionally, if you compose a line of five items or more, you will get a colored bonus brick at the bottom of the screen. Selecting this brick you will remove all planets of the same color from the screen. But if you use one brick, you will lose all bricks you have received before.
One shift of a planet is one game move. At each next move, the computer will place three new planets on your field. But having composed a line, you will get one bonus move to be ahead of the computer.
But the zest of this game is the mission bar right below the game field. It shows you the color sequence you have to follow to destroy the planets.
If you have managed to match the first mission item, you get your score doubled, the second one - tripled, and so on.
After completion of each mission, you get a rocket. Rockets are targets for you as well as planets, but they provide you with additional 1000 points per line.
Remember that ignoring an assigned mission for a long time will put you in trouble - planets will appear more faster and in the most unexpected places.