20 years ago, I made a Space War clone in GFABASIC with ship movement but it lacked correct physics. It was my first remake for publication, see http://paradize.final-memory.org/games.shtml -> Space Battle If someone want to cut his teeth, I have the base source from 1994/95 somewhere without fancy graphics, men, sound or joystick options. But it was the basic elements without correct physics. Take the attached source without warranties as a little Easter gift for upcoming Atari coders.
Take care and have a Happy Easter! SSB