OpenTyrian is a port of the DOS shoot-em-up Tyrian from 1995. Tyrian is an arcade-style vertical scrolling shooter that gets very crazy, very fast!
You play as the terraformation pilot, Trent Hawkins who is being hunted by the evil corporation Microsol because of his knowledge of the material Gravitium which has the power to control gravity. The story plot is moved along through the collection of Data Cubes which contain transcripts (or sometimes advertisements) of various communications between Trent and other parties along the way.
http://www.bluenexus.net/Reviews/OpenTyrian/OpenTyrian-review-01-15-11.html