Just wanted to point out...
... to the people saying he stole Tyrians graphics, he did credit Daniel Cook (credited as his nickname Danc) for the graphics.
Tyrians source code was licensed for a small group of developers in 2007. Following that announcement, in April 2007 Daniel announced the free availability of his Tyrian artwork under generic liberal terms.
http://www.lost garden.com/2007/04/free-game-graphics -tyrian-ships-and.html