7. Star Citizen
One of the most ambitious, albeit controversial, titles that has been stuck in development hell, Star Citizen has been in the works since 2010.
Pre-production on the game began back in 2010, however it was in September 2012 that its reputation began to make a splash in the gaming space. Announced via a successful crowdfunding campaign on Kickstarter that raised $2 million, Cloud Imperium Games' title was set to be one of the most expansive and ambitious video games ever released.
Seamless space-to-ground transitions, PvP modes, a cooperative campaign featuring Mark Hamill, and huge spaceships with explorable interiors have all been teased, but progress on Star Citizen has been slow (to be generous) since being opened up to the public.
Despite the Kickstarter closing in 2014 in line with the initially planned release date, Cloud Imperium have continued to raise funds by selling various in-game items.
To date, estimates have put the total amount raised for the game somewhere in the $500 million mark, raising plenty of concerns over whether or not these players who have invested for over a decade now will ever get their hands on a finished copy of the game.