Duake puts the Doomguy in Quake

Mashing two of the greats together, Duake brings the Doomguy along with their full arsenal into the classic Quake. Created by a modder with a slightly amusing name, Magic Nipples, this isn't just some basic mod that just dumps a Doom model into Quake, it includes:

• Added Doomguy, and his arsenal of weapons (duh).
• Added 2 HUD types for the full Doom hud and a Doom 64 like minimal HUD.
• Added the rifle to replace the nailgun.
• Completely redone episode 1 of Quake with colored lighting, colored water, new props, enemy placement, and the inclusion of some episode 2-4 enemies on hard difficulty.
• Added a new wall demon enemy as seen above.
• Added a spectre mode for the Fiend.
• Reworked some of the enemies to have different attacks or adjusted attacks.
• Reworked the Chthon fight to be much more interesting.
• Added a few new secrets here and there.

The developer even made a trailer for it:

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For it you do need to own a copy of Quake as it uses the PAK files from it. There's also currently only a downloadable Windows build, but I've verified that it seems to run nice with Wine.

Could be your fun distraction for the week.

You can find it on Mod DB along with the instructions. The source code is also up on GitHub.