Frozen Bubble is a free software Puzzle Bobble style computer game which is available on several operating systems including Linux, Windows, Mac OS X, the Symbian Series 60, Windows Phone 7 and Android line of smartphones. There is also a single player Java applet version.
The original Frozen Bubble was written in Perl by Guillaume Cottenceau, and uses the Simple DirectMedia Layer (SDL) library. The game features 100 levels and includes a level editor. Like many popular free software/open source games, it features penguins a la Tux, who in this game shoot the coloured frozen bubbles to form groups of the same colour. Such groups disappear and the object is to clear the whole screen in this way before a bubble passes a line at the bottom.
Version 2.0 offers multiplayer play via LAN and Internet. Two players can also play on the same computer. This version is presently for Unix-like operating systems (such as Linux, Mac OS X, etc.) only. The chain reaction mode (where fallen bubbles will zoom back up to complete triplets, possibly falling more bubbles and thus creating more combos) is also available in network mode as of Version 2.0, and greatly changes the mechanics of the game.
The game is released under the GNU General Public License.
Source: Wikipedia, "Frozen Bubble", available under the CC-BY-SA License.