A nice little game about exploring a solar system.
https://www.indiegogo.com/projects/trippin-planets--2#/I wrestled internally with the idea of putting this in the FE investigations because the developer actually used F = G((m sub 1m sub 2)/r^2) for gravity and the physics system in Unity for his game and when I asked about it he was friendly enough to share his setup Unity/Playmaker.
But I figured it was best in here because it's a cool looking game regardless.