Hrm...
Dark Castle was released in 1986, so this sequel came 22 years after the original. Duke Nukem was released in 1991, so DNF is presently 17 years after the original. (Assuming, snicker, that it gets done this year.)
Return to Dark Castle started development in 1996, so it took 12 years from beginning of development. Duke Nukem Forever started develoment in 1997, so not only is Return to Dark Castle a later sequel, it took longer to develop! (Again, assuming, giggle, that DNF gets done this year.)
Dark Castle was released in 1986, so this sequel came 22 years after the original. Duke Nukem was released in 1991, so DNF is presently 17 years after the original. (Assuming, snicker, that it gets done this year.)
Return to Dark Castle started development in 1996, so it took 12 years from beginning of development. Duke Nukem Forever started develoment in 1997, so not only is Return to Dark Castle a later sequel, it took longer to develop! (Again, assuming, giggle, that DNF gets done this year.)