Summary
The game is typically experienced as a simulation, allowing the player to strategically deploy emergency forces—rat exterminators, police officers, firefighters, and eventually military units—to regions affected by the spreading rat threat, while equipping them with available tools. Additionally, the player can assign up to ten researchers to develop new weapons, defenses, and powerful super weapons to combat the infestation and gather critical information to advance in the game. If the rat menace extends beyond London’s borders, reaches the Research Center, the Government Center, Harris' apartment, or if all emergency units are eliminated, the game ends.
Between simulation gameplay, the game unexpectedly shifts to a playable character in a randomly selected text-based adventure. The player must choose one or more dialogue options to perform actions that help the character survive the rat threat and avoid death. While it is not essential to keep the characters alive, successfully saving them rewards the player with extra reinforcements.