ZDoom is an enhanced port of the official DOOM source code to Win32. As such, it not only works with (and requires) Windows 95/NT 4.0, but it also adds new features not found in the version published by id Software.
ZDoom may be used and distributed free of charge. No profit may be made from the sale of it.
ZDoom was created by Randy Heit using id Software's and various others' sources.
ZDoom now comes in multiple flavours! The primary port, GZDoom, sports advanced hardware (OpenGL) and enhanced software rendering capabilities, while its sister port QZDoom serves a test bed for new (stable) features.
These details are provided for information only. No information here is legal advice and should not be used as such.