ExoSim is a exoplanertary system simulator using CSS and HTML and the piskel.app pixel art software for art. We use NASA Exoplanet Exploration's software, Eyes on Exoplanets for accurate and approximate stats. To launch the game, simply go to the .zip file and extract the files, and open the folder, then click launch.html and it should open up the Main Menu.
Sincerely, the devs