Warhammer 40,000: Dark Millenium
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Warhammer 40,000: Dark Millenium was originally an MMO that was being developed by Vigil Games (creators of Darksiders). Unfortunately, due to THQ's financial problems (their unwise decisions over the past years being the cause) Dark Millenium was then changed to a Single-player title with multiplayer modes. Thanks a lot THQ for making five years of development a waste.
Vigil Games has stated that the new Dark Millenium will be more like Warhammer 40,000: Space Marine (to clarify, it will feature space marines real time shooting and hack and slash). Though whether they will keep the RPG elements or not is currently unknown. It is also unknown if Dark Millenium's single player will focus on one race or more.
However, due to THQ's said financial problems, it would only be a matter of time before they decide to cancel it or if they go bankrupt.