This level occupies the map slot MAP23. For other maps which occupy this slot, see Category:MAP23.
MAP23: Hatred is the twenty-third map of Requiem. It was designed by Dario Casali, and uses the music track "Dry Rot" by Mark Klem. It is one of a few Doom II levels which make intentional use of ghost monsters, created by having an Arch-Vile resurrect a monster who has been crushed. It also features a battle with the final boss.
According to both the text file and the Requiem info pack:
This map is a taste of what Final Doom is all about - unleashing the potential of the DooM2 [sic] engine.
The level incorporates a unique use for the Archvile [sic] ghost making technique, where it can resurrect a demon giving him the ability to walk through walls and not be shot. The first known way to kill such an enemy is to hit him in a rocket explosion. Another way is to get the ghost to hit another enemy who has a close attack ability, who will then go and tear the ghost apart.
While traveling through the sewer, a portion of the northern wall is misaligned. Press on it to activate a lift with a blur artifact on top. This lift leads to a megasphere and a yellow key-locked door leading to the same destination as the other one. (sector 114)
Open the door leading into the building where the red key is, and head into the west of the building to find a switch, which must be pressed before the door closes again. (sector 240) If this switch is flipped before the final boss battle begins, the floor on which the final boss sits will be unable to lower, making any rockets fired at it guaranteed to connect. Moreover, if you hit monsters in the corridor just behind the Icon of sin, you can make damages to the Icon.
In multiplayer, the Icon of Sin will not be present. However, this level does not contain an exit linedef, preventing you from leaving the level in multiplayer gameplay unless a timer has been set through the -timer switch. The Deathmatch Repair File created by Steve Terry adds an exit switch found in the easternmost of the tunnels leading down to the sewer. During single-player gameplay, this exit will be closed off, requiring you to complete the level in the intended fashion.