support for up to four players. This version also has new lighting effects, mostly seen in gunfire, and also uses the Expansion Pak for extra graphical detail. This port also features an entirely new soundtrack, consisting mostly of dark ambient pieces, composed by Aubrey Hodges. A port of Quake II was included with Quake 4 for the Xbox 360 on a bonus disc. This is a direct port of the original game, with some graphical improvements. The port allows for System Link play for up to sixteen players, split-screen for four players, and cooperative play in single-player for up to sixteen players or four players with split-screen alone. Unofficial In December 2018, Polish programmer Krzysztof Kondrak released the original Quake 2 v3.21 source code with Vulkan support added. The port, called vkQuake2, is available under the GPLv2. Mods As with the original Quake, Quake II was designed to allow players to easily create custom content. A large number of mods, maps, graphics such as player models and skins, and sound effects were created and distributed to others free of charge via the Internet. Popular websites such as PlanetQuake and Telefragged allowed players to gain access to custom content. Another improvement over Quake was that it was easier to select custom player models, skins, and sound effects because they could be selected from an in-game menu. Mods for the game include Action Quake from 1999. PC Gaming Worlds Simon Quirk wrote of the game, "The Action Quake team fancied a multiplayer-only total conversion of Quake II where strategy, accuracy, and cool-looking fights would dominate." Release Quake II released on December 9, 1997, in the United States (one day short of the release of Doom four years prior) and on December 12 in Europe. Despite the title, Quake II is a sequel to the original Quake in name only. The scenario, enemies, and theme are entirely separate and do not fall into the same continuity as Quake. id initially wanted to set it separately from Quake, but due to legal reasons (most of their suggested names were already taken), they decided to use the working title. Quake II was also adopted as a name to leverage the popularity of Quake according to Jennell Jaquays. Quake II has been released on Steam, but this version does not include the soundtrack. The game was released on a bonus disc included with Quake 4 Special