rated M by Australia's rating board for Xbox 360. The game was previously classified by Korea's Game Rating Board and has yet to be accompanied by an announcement by Microsoft. As in Korea, the Australian classification request was submitted by Microsoft. Take-Two Interactive, the go-to publisher for Duke Nukem-related info, tells Joystiq it is not "publishing this title and [doesn't] have any info."
We've followed up with Microsoft for a nuke of knowledge on what their plans are. In the meantime, the PC version of the competent 2002 side-scroller can be found on GOG.com for $6.