Serious Sam Rusutaku Assault! Proof of Newton's law of gravitation

In Scene 2 of the Rusutaku Assault! campaign for Serious Sam the second encounter, the light bulb in this huge hall appears to gain an abnormal amount of mass while gravity of the Earth is lost, causing every moveable object in the game to either orbit around the sphere or crash on it. This simulation of physics proves Newton's law of gravitation because the orbit of Serious Sam around his light bulb is like that of a planet around its star: an ellipse where the star is in one of the foci, and with increased speed close to the star. We defeat the boss in the room while orbiting around the light bulb, which is ideal to avoid objects fired by enemies. I'm playing Rusutaku Assault! under the Serious Violence 3.0 mod.