They Hunger 2: Rest in Pieces

The second part of a horror oriented total conversion mod for Half-Life made as a promotional game for PC Gamer.

The protagonist begins the game where the last left off: unarmed and trapped, however just as the a zombie is about to enter his cell the player is saved by a police officer with a military-equipped truck. Still unarmed, the player is forced to restock his arsenal himself (though it is possible to re-enter the police station and regain several lost weapons). The player soon after enters the sewers. There he encounters bizarre aquatic creatures, he also encounters several state police officers who have been zombified after arriving at the town. The player later makes it to the Rockwell water treatment plant, it becomes apparent that the army has been sent in to take care of the zombies and kill all civilians (possibly because of the risk of contamination.) A major part of this episode is spent exploring 'Rockwell asylum for the criminally insane' operated by Dr. Franklin. Once inside the player meets Alfred, Dr. Franklin's former assistant, who tells the player that it was he and Dr. Franklin that discovered strange things in the city water that brings anyone alive or dead to a state of half life. He tells the player that Dr. Franklin was trying to figure out how it was causing the zombies but ended up being infected too. The player then enters Dr. Franklin's under ground laboratory where he witnesses several of the doctor's horrid experiments, such as dismembered heads being kept alive. Soon the player is forced to fight an army of undead Frankenstein-like monsters brought to life through Franklin's machine. Afterward Dr. Franklin is chased out of the area by one of his own monsters. The episode ends with the player inadvertently setting the whole asylum aflame. The player and Dr. Franklin are caught in a massive explosion which ends the episode.