BZFlag is an online multiplayer first-person shooter video game that has been developing since 1992. The game is available on platforms such as Windows, MacOS, Linux, and Solaris and has been developed primarily in C and C++. The game's objective is to destroy your opponents using a tank and avoid being destroyed yourself. Tanks can be equipped with different weapons and abilities, and the game includes various maps and game modes.

It was created as a spare-time project by Chris Schoeneman, who rewrote it in C++ to enter an SGI competition. Since then, the project has been carried on by a dedicated volunteer team and released under an open-source license. Currently, the game has an estimated 100 players online at any given time of day, although many more have it downloaded and installed.

The game is popular with a wide variety of players, from those looking to kill time to those looking for a friendlier, less violence-focused community. The game also has an active community on forums, and IRC channels, and players, such as a replica of Stonehenge and an entire European castle, have created some impressive maps.

One of the most notable aspects of BZFlag is its custom game mode, which allows players to create their maps and game modes using available editing tools. This has allowed the community to create different unique content and gameplay experiences.

The developers started programming the game in different ways. Tim started working on the game while working for Caldera Systems and looking for games to add to OpenLinux. Jeff got involved with the game in 1996-1997 and worked on making it run on Windows. Dave B started programming the game after playing for a couple of months and realizing he would never be a good player. David T began to write the first 3D world editor in 2000 and then worked on BZFlag itself in 2001. Sean started getting involved with the game after downloading and playing it on MacOS X in 2002 and then joined the developer community on IRC.

The programmers have also faced several challenges over the years. One of the biggest challenges has been keeping the game up-to-date and relevant as technologies and platforms evolve. Another significant difficulty has been the lack of time and resources to work on the game, as it is an open-source project developed by a team of volunteers. The developers have also mentioned the difficulty of attracting and retaining new developers and contributors, as the game has a relatively small community compared to other similar games.