I have two young boys, aged 4 and 6. They both enjoy video games, and I let them play Genesis and Super Nintendo games. The other day I was playing Contra 3: Alien Wars, and they walked in and saw me playing it, and they wanted to play. Now, Contra 3 isn't really a "mature" game, but at the time of it's release, back in early 1992 if I'm not mistaken, alot of parents wouldn't let their young children play a game like Contra 3. It was a game that people would maybe let their teenagers play, but the little ones would be told to play Mario and Sonic and stuff like that.
Of course, in comparison to the games we have today, a game like Contra 3 is considered pretty juvenile. Sure it has violence and such, but the graphical nature of the game is pretty primitive compared to modern games. Since Contra 3 has come to the virtual console of the Nintendo Wii, it had to be rated by the ESRB. This time, it got a rating of E10+ for fantasy violence. If the ESRB existed in 1992, I wonder what it would have rated Contra 3 back then. I'm guessing T for TEEN.
Take another game like Splatterhouse for the TG-16. This game was also recently released on the virtual console, and it got a rating of T for TEEN. For Blood and Gore and Violence. Streets of Rage on the Wii's Virtual Console got a E10+ for violence.
It's just interesting to think about how these older games would have been perceived back when they first hit the scene, compared to today, when the graphics are considered very primitive in comparison to the modern consoles. A game like Alien 3 on the SNES, might have seemed very scarry when it first was released. It might have recieved a M for Mature rating had the ESRB existed back then. Today, it still probably isn't appropriate for very young children, but for most kids it would be no big deal.