According to information seen on their web sites, well-known game retailers have changed the release date of Mighty No. 9 for 2016, instead of the original Sept. 15 launch in the Americas and Sept. 18 worldwide.
US stores Amazon, Best Buy and GameStop posted on their sites the console version of the game will be on sale on the apparently placeholder date of Dec. 31, 2016 and a “not yet announced” one.
The date change has not been made on Steam where it still indicates Sept. 15 for the Windows version of Mighty No. 9.
No information has been updated from Comcept or Deep Silver about the date change.
This likely seems to indicate there will be a delay; hopefully we’ll hear something on Monday or later.
[Source]: Polygon: Retail listing changes suggest Mighty No. 9 is delayed to 2016.