About
Quake II is a 1997 first-person shooter developed by id Software and published by Activision, the second installment in the Quake series, in which a lone space marine fights the Strogg on their homeworld after a squad's crash-landing. Q2PRO is an enhanced Quake II client and server for Windows and Linux, adding a unified OpenGL renderer, an improved console with command history, separated rendering/physics/packet rates, ZIP packfile and JPEG/PNG texture support, MD3/MD5 model support, Ogg Vorbis/Theora audio and video, OpenAL multichannel sound, and demo/broadcast tooling; it requires the original Quake II game data to run, and has no numbered releases, only nightly builds.
How it differs from the original
Adds substantial technical and network enhancements over stock Quake II — including higher-quality textures and models, an extended protocol for larger maps, frame-overflow elimination, and protection against corrupted game data — while still depending on the original Quake II assets to play.
Getting started
Requires an existing copy of Quake II's game data; there are no official numbered releases, so players are directed to the latest nightly build, and Linux users are expected to build it from source using the project's included build instructions.