A post on the Mighty No. 9 website announces that this Mega Man homage is gold, and is due on June 21st in North America and June 24th elsewhere. Keiji Inafune says there will be no further delays and these dates are "set in stone," though the portable versions for PlayStation Vita and Nintendo 3DS "will follow at a later point." Here's more on the news:

It has been almost three years since the start of our Kickstarter campaign, which was only made possible through the support of our backers and fans around the world. This is a project where everyone’s passions were combined in order to create something very special, and we are looking forward to delivering the final product to everyone who was involved. There can be no stronger connection between game creators and game fans.

Now that the dust has settled, we will be delivering Mighty No. 9 to everyone next month. How long will it take you to clear the main story on NORMAL? How many people are going to be able to clear MANIAC mode? What is going to be the fastest record for the time attack mode? We are looking forward to seeing the community answer all of these questions for us! Make sure to let us know your feedback and thoughts on the game through our SNS channels as you play the game. Your voices are what made this game possible, and we want to continue hearing what you think so that it may influence our future endeavors. “