The Best Way to Play Classic Doom

All you need to know

1. Install "Doom + Doom 2" on Steam.
2. Download the latest version of UZDoom from https://www.zdoom.org/downloads. It will automatically find the game files from your Steam installation.
3. For playing custom maps and mods, use DoomRunner to store mod configurations and launch the game with them.
4. For playing multiplayer with custom maps and mods, use Zandronum, a related Doom port with proper multiplayer netcode added (but with less compatibility with newer mods intended for UZDoom).

Details

UZDoom supports full mouselook with proper perspective rendering that doesn't stretch as you look up and down. It also supports many custom maps and mods that the official release alone doesn't.