At this point, the best thing that could happen to Keiji Inafune's Mighty No. 9 is if Capcom straight-up sued. Free marketing, great debate, battle lines would be drawn. We don't know what the grounds for the lawsuit would be, but the latest footage of the game comes so close to sharing similarities with Mega Man, it's almost difficult to tell the two apart.
Go ahead and test it yourself. Take the Mighty No. 9 footage found after the break and play it to someone who has general video game knowledge. Take out all the context and just ask: What game is this? Actually, please go ahead and do that and let us know what the other person says.