from wikipedia :
Originally in development under 3D Realms, director George Broussard, one of the creators of the original Duke Nukem game, first announced the title's development in April 1997, and various promotional information for the game was released between 1997 and 1998. After repeatedly announcing and deferring release dates, 3D Realms announced in 2001 that it would be released simply "when it's done". No official video of the game was shown for almost eight years, until 3D Realms released a new teaser trailer in December 2007, but the game "sank" yet again soon afterwards.
In May 2009, 3D Realms was downsized for financial reasons, resulting in the loss of the game's development team. Statements by the company indicated that the project was due to go gold soon with pictures of final development. Take-Two Interactive, which owns the publishing rights to the game, filed a lawsuit in 2009 against 3D Realms over their failure to finish development. 3D Realms retorted that Take-Two's legal interest in the game was limited to their publishing right. The case was settled with prejudice and details undisclosed in July 2010.
On September 3, 2010, after fourteen years, Duke Nukem Forever was officially reported by 2K Games to be in development at Gearbox Software. It was originally confirmed to be released on May 3, 2011 in North America, with a worldwide release following on May 6, 2011. This was, however, delayed by a month to June 10 internationally, with a North American release on June 14.
On May 24, 2011, it was announced that Duke Nukem Forever finally "went gold" after 15 years. After going gold the launch trailer for Duke Nukem Forever was released on June 2, 2011, quelling any doubt that release was anything but imminent. On June 27, 2011, Aspyr Media announced that Duke Nukem Forever would be making its way onto Mac OS X in August 2011. It was made available for pre-order on June 27 via their online game distribution platform GameAgent.