There was a download of GZ3Doom 1.8.6 on the developer's website when we last checked. We cannot confirm if there is a free download of this software available. The most popular version among the software users is 1.8. The program is included in Games. We recommend checking the downloaded files with any free antivirus. The actual developer of the free program is zdoom.
From the developer:
GZ3Doom is a modification designed for the gzdoom game that adds several stereoscopic 3D modes, including one for the awesome Oculus Rift virtual reality headset. It also provides split hud and menus for side-by-side vr_modes 3 and 4, position tracking support and you can use Oculus SDK frame timing.
You may want to check out more software, such as Ballmaster 2, Virus or Bomb John, which might be similar to GZ3Doom.