The weapons the player starts with will vary from map to map for example, in Hangar, the player has only the Doom 2016 Pistol, whereas in Nuclear Plant and Toxin Refinery, the Pistol and Shotgun. Weapon pickups are the literal counterparts in the 2016 game, so the Chaingun in Classic Doom becomes the Doom 2016 Chaingun rather than, say, the Heavy Assault Rifle. This level contains a secret exit leading to E1M9: Military.

It was designed by John Romero and uses the music track 'Dark Halls'. The Classic Maps are played in the same way as the small sections that unlock them do, with Classic map layouts, wall textures, and objects, but with the player's HUD, weapons, and enemies from the Doom reboot. E1M3: Toxin Refinery (MAP03 in PSX / Saturn / Jaguar / 3DO / GBA / 32X) is the third map of Knee-Deep in the Dead in Doom. The classic map fragments beginning with the Toxin Refinery fragment in the Argent Facility do not have any enemies at all, but do usually provide equipment for the player. The game consists of four episodes and eight missions in each episode (each with an additional secret level, which is called mission 9.

Every mission in the game (excluding levels with bosses) have one classic map. Doom is a very fast-paced game, as stated before. This area consists of one section of the classic map that is unlocked, but with enemies from Doom (2016) replacing the classic enemies, and classic health, armor, and ammo pickups that do add to the player's Doom 2016 equipment. You can unlock 13 maps (levels) from the classic Doom released in 1993. They are discovered by finding a hidden lever in each level, that opens a secret door, and then entering the 16-bit texture mapped area hidden behind the opened door. Classic Maps are unlockable maps and campaign based on classic Doom and Doom II levels found by discovering retro secret areas in the main campaign of Doom (2016).

Doom classic maps locations