Gravity: Friend or Foe? is a physics-based puzzle game. You can move the sun with your mouse but the planets can only be controlled through gravity.
Gravity is both your friend and your foe. You should keep your planets inside the screen but you shouldn't let them touch the sun. Collect power-ups and try more dangerous maneuvers for more points.
Donwload the appropriate bundle depending on whether your system is 32 or 64 bit. Extract and run 'launch.sh'.
Download the appropriate installer depending on whether your system is 32 or 64 bit. Run the installer to install the game and find the game in your start menu.
Or try the portable versions: 32-bit | 64-bitGravity is Open Source. You can find the complete source code on Github.