Shigeru Miyamoto has stated that one of his main concerns for the Mario series is that it doesn’t become too childish, so that a wide range of age groups can enjoy what the iconic series has to offer.
“I realized that whether it’s story or movies, it’s not about whether we need them or don’t need them. What’s most important is that the game resonates. You notice things like how a certain enemy wasn’t scary, but the next time a similar one appears, its color is a little different and it spits out two rocks instead of one, so you think it must be tougher. You reason things out for yourself and put them to the test. This kind of interaction is interesting.”
“Unless you’re careful, there’s a tendency for games like Mario that can be played by children to gradually become childish. Those making the game tend to unconsciously make them that way. Taking how Mario’s line can be scripted as an example, they even propose to write, ‘Where’d my mommy go?’
“When someone in their fifties like me hears their player-character speak childishly like that, it doesn’t quite sit right. After all, Mario wasn’t a game only for children in the first place. As I make a game, I try to keep in mind that guys in their fifties will play it, too.”
– Shigeru Miyamoto, Nintendo