The game was "intentionally designed as a cross between "Halo" and "Silverado"." O'Connor said "Halo" was "of course" an inspiration, comparing "Darkwatch" to the horror aspects of "Halo", and senior designer Brent Disbrow said he expected it to "stand on par with games like "Halo 2"." Other video game inspirations recounted by O'Connor and Valdez included "Half-Life", "Medal of Honor", "Metroid Prime" and "TimeSplitters". Lead level designer Matt Tieger said that a creation of one of the game's bosses was "inspired by all the fun" that he had while playing the "Metal Slug" 2D shooter series with its "crazy bosses". O'Connor said the game's reputation system was inspired by the contrast between the Old West figures such as Billy the Kid and the likes of Wyatt Earp, who "both were feared gunslingers, but one was a psychopathic killer and the other was a good guy/lawman."