Algodoo

Now with auto-docking, simplier, pretty reliable, and walls collide with A (are closed) when undocked.

Reliability improved, now can dock at pretty high speed, and when modules are not straight.
Now there are totally no problems with undocking.

Yet another edit
Added small shuttle thing, and armor piercing railgun/cannon.
Projectiles pierce station walls, and smash any unlucky people inside. Can cause modules to undock too.