Dyson was developed as a part of the inaugural TIG Source Procedural Content Generation Competition.
Use of Procedural Content Generation Methods
From the thread on TIG Source:
All of the visuals except for the font and the palettes (and the location of UI elements etc of course) are generated procedurally. The game generates a number of textures at startup, mostly based on trigonometry and inverse-square laws. The asteroids are then distributed randomly around the system, sorted so they aren't too close together, and then the players are scattered around. The trees are L-Systems, that I modified to grow in real-time. The elemental make-up of an asteroid is determined randomly, but affects the appearance of the seedlings generated on each asteroid. Leaner ships with prominent wings haf a high speed rating, while the seedlings with larger noses have a higher strength rating. Energy affects overall seedling size. The root systems grow over time to become fairly interesting networks.