You are in the process of being moved between prisons when the train derails. With nothing to lose you run. But the situation you find yourself in may be worse than confinement…
You need a full copy of Quake 1. If you don’t own Quake yet you can get it on GOG.com for a few bucks.
The mod features custom maps, music and QuakeC.
During development the mod was tested with QuakeSpasm. Using this source port is guaranteed to work, but most others should function as well. Realtime lighting (as provided by i.e. DarkPlaces) may not understand all lights used in the maps. Stick to the pre-baked lightmaps instead.