The episode consists of nine levels in all, eight standard levels and a single secret level, as a homage to the similarly structured nine-map episodes in the original Doom, particularly Knee-Deep in the Dead. As Doom II did not have episodes per se calling No Rest for the Living an episode is technically a misnomer. The new maps are a separate selectable campaign at the inception of the game, in a fashion similar to Doom's episode selection. Selecting "Hell on Earth" propels the player into the classic 32 map Doom II campaign, whereas selecting "No Rest for the Living" starts the new 9 map addition. Completing No Rest for the Living in singleplayer on any difficulty unlocks the "And Back Again" Achievement, and unlocks the "Doom II Marine Suit" Avatar award.
According to Nerve Software boss Brandon James the expansion set "continues on Earth after Hell's forces have [seemingly] been vanquished".
The goal of the expansion is to travel to a pocket dimension of Hell and assassinate a Cyberdemon that has been building an army of demons for his own personal use. No Rest for the Living takes advantage of the expanded capacity of modern systems, with significantly more enemies on-screen at the same time than in the original Doom 2, especially in the later levels.
- Level 1: The Earth Base
- Level 2: The Pain Labs
- Level 3: Canyon of the Dead
- Level 4: Hell Mountain (Exit to secret level)
- Level 5: Vivisection
- Level 6: Inferno of Blood
- Level 7: Baron's Banquet
- Level 8: Tomb of Malevolence
- Level 9: March of the Demons (Secret level)