Chromium B.S.U. is a fast paced, arcade-style, top-scrolling space shooter on Windows, iPhone, PSP, Mac, AmigaOS 4, Linux and numerous other UNIX-like operating systems. It is a free software distributed under the Artistic License. The original version of Chromium B.S.U. was designed in 2000 by Mark B. Allan and released under the Artistic License. Since then it has received the contribution of numerous people in the open source community. The gameplay is based on a player who plays the role of hero, shooting their way through a barrage of enemy forces. The game is similar to 2D top-scrolling space shooters played in arcades.