the game was cancelled. Both Game Boy versions were eventually released in compiled format in 2007 as freeware by World Tree Games. In the Game Boy Color version, the Full Game incorporates a shorter story (from Episodes 1-4) than the original DOS game, but planet Ixmucane core always gets destroyed at the end, and the levels were redesigned. The rear weapon from the DOS game is not available. The player can carry two Sidekick weapons at once, but only one is usable at a time. New game modes and items can be unlocked by purchasing Extras using credits obtained by completing a stage. The Game Boy Advance version incorporates graphics from the DOS game, but the level layout and game play are based on the Game Boy Color game. Two Sidekick weapons can be fired at the same time. Super Arcade and audio are not included. New to this game is Challenge mode, where additional levels are unlocked by completing existing Challenge levels. OpenTyrian In February 2007 the Pascal (and x86 assembly) source code for Tyrian was delegated to a small group of developers to re-write it in C, in a project named OpenTyrian, licensed under the GNU GPL-2.0-or-later. Jason Emery released Tyrian in 2007, along with some Game Boy and Game Boy Advance versions. Following that announcement, in April 2007 Daniel Cook announced the free availability of his Tyrian artwork (not including the later work for the Game Boy Color edition and for Tyrian 2000) under generic liberal terms of the open content Creative Commons Attribution 3.0 License. OpenTyrian was originally stored on the BitBucket repository before moving on to GitHub. Audio The music of Tyrian was created by Alexander Brandon with additional music by Andras Molnar, and is in the LDS (Loudness Sound System) format. The Tyrian 2000 CD includes 25 of the tracks in red book audio format. The red book tracks are omitted from the freeware version due to the download size. The tracks "ZANAC3" and "ZANAC5" are reproductions of two songs from the MSX/NES game Zanac. Alexander Brandon released the music of Tyrian for free in August 2010. Reception The game mostly received positive reviews. Tyrian scored 87% in PC Gamer (one percent below their Editor's Choice award). A reviewer for Next Generation complimented the use of a shop system for acquiring powerups, the ability to save games at any time, and the inclusion of