веÑ, pronounced "Ves", is an Open-Source (GPL v2) 2D gravity/orbit simulator, written in C# - powered by SFML, that I've been working on and playing around the last few weeks. Just a little side project I worked on when ever I was bored, fun to screw around with when you are bored.
There are no goals, for it is simply a sandbox game. Create planets, play around with objects, destroy them. You can even spawn a controllable space ship, level it up, and destroy the solar system you just created with it!
There is no way you can't open a RAR file. I swear every distribution of Linux I have ever used comes with an archive manager that can handle EVERYTHING.