OG : Orbit Game
This game allows you to play with the orbit of a planet around a star. Its fairly simple, as you score one point per orbit.

The calculations are correct to the 16th decimal point, so the amount of orbits you can get is difficult to predict in advance. Some features, are scientifically accurate, like the general physics of gravity expressed 1/r^2. So gravity decreases at an inverse proportion of the square of the distance that decreases.

Features like cosmic drag (collisions with meteors) and solar wind (radiation from the sun) have been exaggerated for the sake of the game play, but otherwise their effect is standard geometry.

You can alter the speed of the universe, or set a vapor trail to track your orbit. The vapor trail changes color when the x and y momentum reaches 0 to give you a clue as to how circular your orbit is.

The OG zone (zero gee) is when the planet moves too close to the star, and should impact. For the sake of simplicity, your score will instead be set to zero, and gravity is turned off. This makes the game easier, and the programming too. You graduate to a new planet every few orbits, but this is just for fun, and will only effect the vapor trail slightly.