Children see the world with different eyes, in the case of some video games it is a good thing, because what Link, Kirby and Donkey Kong do in some games is more for adults.
As an innocent kid, you might not have been able to see it, but some of your childhood games had some content that wasn't quite as adult-friendly. As a rule, they were well hidden, so that only a look as an adult reveals what some developers were hiding from you at the time.
From adolescent sayings to drunken fighters to dead parents, in some games there are things that are more inappropriate for children to see and hear. Often these things were hidden a little in the game, but sometimes they were presented quite openly.
Although the list is only an excerpt, Nintendo is surprisingly often represented. Allusions to alcohol and sex can be found more often with Kirby, Link and Mario, but many things have been censored for international use or over time.