: This is the most reliable source for standalone files. You can find the DMQ2 (Deathmatch Quaked) mod, which is a "pro mod" of DMC that works with the older WON/WON2 (World Opponent Network) versions of Half-Life. It effectively functions as a standalone experience once unzipped into a compatible game folder.

A standard retro game folder should consist of .wad , .bsp , .mdl , and .dll files. Be highly suspicious of standalone .scr or .msi files masquerading as maps or mods.

Standalone directories make it significantly easier to install custom maps, weapon skins, and community patches.

Owning a portable, executable copy ensures you can play the game regardless of future digital distribution changes.

: You can run the game directly from a USB drive without installing background services.

This gives you a standalone folder that runs DMC without the Big Picture mode, friends list, or overlay.