In 1985 this seminal title combined strategy, resource management, tech trees and real-time text adventure vignettes to incredible effect. Based on James Herbert's grisly 1973 horror novel (and released by Herbert's own publisher Hodder & Stoughton), the game tasked you with containing, researching and, eventually, eliminating a plague of giant mutant rats busily chomping their way through Greater London's terrified populace.
The game seamlessly interchanged R&D elements with resource management as you placed police, fire-fighters and specialist ratkill units across the map in response to public sightings. Every five minutes or so, a terrifying siren would signal the start of one of the game's incredibly tense 'real-time text adventure' scenarios, where you played as one of the characters in the book.
Played out with an underlying 'thud-thud' heartbeat to convey varying levels of tension, you were given a basic outline of your surroundings, and then had to quickly construct simple commands from a multiple choice menu of words. It was effectively the first ever point and click adventure, three years before LucasArts' Maniac Mansion.