IGN - Miyamoto says 'don't worry', Super Mario Run will be challenging

Coming from an IGN interview with Shigeru Miyamoto...

“A big point with this game is, ‘How can we make this a game that people who aren’t good at games can play the game and enjoy it?’ But also at the same time, we’ve been making Mario games for a long time, and we know how to make them challenging. So if you’re a Mario fan, I don’t think you have to worry about that part of it.”