I used to have a physics sandbox game called Phun. It was fairly fun, but I hadn't used it for a few years.
I recently downloaded the more recent version, now called Algodoo, and gave it a go.
Of course the first thing I do is recreate Kerbal Space Program.
Here we have a successful rendezvous with the orbiting craft:
Docking complete:
What a
lovely orbit. And when the game is in motion, you can see a curious effect. Because one ship is closer to the planet, it has a lower orbit and therefore has a higher orbital velocity. Normally in a stable orbit an object wouldn't rotate relative to the background (unless it was already rotating), but because this ship covers such a large altitude range relative to the orbital height, it begins to rotate clockwise on an anticlockwise orbit.
Detachment:
Retrograde burning to slow the craft:
And touchdown: