Nintendo have announced that they’ve decided to delay Star Fox Zero to Q1 2016. You can find the full statement from Nintendo below.
We have been developing Star Fox Zero for Wii U with the aim of releasing it this year. Although we felt that the development had been progressing well, we now believe that we will need a little more time to work on areas such as the unprecedented discovery that we want players to experience in the game by using two screens, and further polishing the level designs and perfecting the tone of the cut scenes. While we have already reached the stage where it would be technically possible to release the title in time for the year-end holiday season, we want to polish the game a bit more so that players will be able to more smoothly grasp the new style of play that we are proposing.
To the people looking forward to the launch of the game this holiday season, I am very sorry.