A brand new mod has just been released for GZDoom — a 3D-accelerated Doom source port — that enables you to transfer features such as enemy behaviours, weapons, assets, and more from the N64 game Doom 64 into the original two Doom games (thanks GBATemp for the spot).
The mod, which is called Doom 64: Unseen Evil, was released last week and is the work of DrPyspy, who was previously behind Doom Delta (a project that aimed to bring together several elements from pre-release iterations of Doom).
It features a new tool called The Terraformer that is capable of transforming any Doom/Doom II level into a Doom 64-style level and also comes with a bunch of cool additional features, resulting in a new way to experience the classic games on PC.
The mod, for instance, incorporates the N64 game's full arsenal of weapons (including the Unmaker) into the original game's levels, reimagines enemies that were missing from Doom 64 (the Chaingunner, the Revenant, the Arch-vile, and the Spider Mastermind) in a similar style, and contains a new difficulty setting called "Redemption Denied" that is based on the enemy placement of PSX Doom.
It also includes a bunch of new audio, such as an original theme from the musician Blue Vertigo, and recycled tracks from PSX Doom and Doom 64.
Here's a description of the project from its author:
"Doom 64: Unseen Evil is a mod for GZDoom that brings the atmosphere of Doom 64 to the worlds of Doom and Doom II. Everything is entirely overhauled: from the player and their weapons, to the halls and the demons that stalk them.
All of the demons that were absent from the original Doom 64 have finally emerged from the deepest pits of hell, including the unsettling Revenant and the sinister Arch-vile. If you're looking for a new challenge, the exclusive Redemption Denied difficulty will bring some of the crueler monster placements from PSX Doom into the vanilla Doom maps.
Proceed with caution; there are many evils yet unseen."
If you want to give the mod a try, you'll need the latest version of GZDoom v4.12.2 (or higher) and copies of Doom I & II. You'll find the link to the mod over on pyspy's website.