The game was purposely balanced so that, while the sidequests are optional to progressing the main story, characters who did not improve their skills and experience by completing sidequests would be too weak to finish the game. To create the detailed talking heads, a sculptor built heads of clay, which the artists studied to determine which parts should be most heavily animated. The heads were digitized using a Faro Space Arm and "VertiSketch", with "LightWave 3D" used for geometric corrections, while the texture maps were created in "Adobe Photoshop". A number of well-known actors were cast as voice-talents. The game's narrations were performed by Ron Perlman, and the prologue featured one of the foremost iconic catchphrases of the game series: "War. War never changes"; Perlman was re-invited to narrate several later "Fallout" games. Other appearances included Richard Dean Anderson as Killian, David Warner as Morpheus, Tony Shalhoub (credited as Tony Shalub) as Aradesh, Brad Garrett as Harry, Keith David as Decker, Richard Moll as Cabot, and Tony Jay as The Mutant Lieutenant. The Master's unique way of speaking was due to his voice being computer-generated and sentences are composed from samples of several people's speech. Interplay intended to use "I Don't Want to Set the World on Fire" by The Ink Spots for the theme song, but could not license the song because of a copyright issue. This song was later licensed by Bethesda for "Fallout 3". The song "Maybe" by the same artists was used instead for the original "Fallout" theme song. At one point in "Fallout"s development, in Junktown, if the player aided local sheriff Killian Darkwater in killing the criminal Gizmo, Killian would take his pursuit of the law much too far, to the point of tyranny, and force Junktown to stagnate. However, if the player killed Killian for Gizmo, then Gizmo would help Junktown prosper for his own benefit. The game's publisher did not like this bit of moral ambiguity and had the outcomes changed to an alternate state, where aiding Killian results in a more palatable ending. "Fallout" ultimately "took just under 4 years to make", according to Tim Cain. The game was released on October 10, 1997. "Fallout" draws much from 1950s pulp magazines, classic science fiction films such as "Forbidden Planet" and superhero comics of Atomic Age: computers use vacuum tubes instead of transistors; energy weapons exist and resemble those used by Flash Gordon.