* ActingForTwo:
** Danny Webb, who voices Inquisitor Drogan, also voices as Cadian Guardsmen and Mira's late superior officer.
** Mark Lewis Jones voices both Lord Nemeroth and Inquisitor Thrax.
* CreatorsOddball: Relic Entertainment, the developers of ''Space Marine'', are primarily known for making RealTimeStrategy games, including the ''Warhammer 40k: Dawn of War'' series. ''Space Marine'' was their first and only shooter ever made, and is remarkably competently made when you consider that fact.
* PlayingAgainstType: Titus is voiced by character actor Creator/MarkStrong, best known for playing villains such as [[Film/SherlockHolmes2009 Lord Blackwood]], [[Film/GreenLantern2011 Sinestro]], and [[Film/Shazam2019 Dr. Sivana]], playing a heroic (by ''40K'' standards) character for once. He would go on to voice Eisenhorn (essentially 40k's version of Sherlock Holmes and James Bond) in the ''VideoGame/EisenhornXenos'' adventure game.
* WhatCouldHaveBeen:
** Originally in the early trailer the game was supposed to be focusing on a squad of Space Marines.
** In some old footage It would have been starring with a normal-looking Tactical wearing a helmet before loosing it later on.
** Promotional images and trailers suggested a Deff Dread boss fight, yet the Deff Dread would not appear as a boss until much later after launch as the final boss of the Exterminatus multiplayer mode.
** The game's director had [[http://www.escapistmagazine.com/news/view/128846-Space-Marine-Director-Talks-Plot-for-Would-Be-Sequels plans for two more games]]; in the second, Titus would've been reinstated into combat under the Inquisition's control (presumably as a Deathwatch member) only to be declared renegade and exiled, and in the third game he would have rallied countless Space Marines to his side and ''formed his own Space Marine chapter''. But thanks to THQ's collapse, these plans were put on indefinite hold if not outright scrapped. A sequel in development by a different studio was eventually announced in December 2021, though it remains to be seen if this reiteration will incorporate elements of the old developers' plans or not.
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