So I just saw Wreck-it Ralph this week, woo-hoo. Here's another little tidbit on it for ya: both Sonic the Hedgehog and his enemy Dr. Eggman make cameos in the movie. Sonic appears making a reference to the "Sonic Says" segment of the old Adventures of Sonic the Hedgehog, explaining the laws the game characters must abide by. He also appears as a guest at Fix-it Felix's thirtieth anniversary party.
Dr. Eggman has a more noticeable role, being one of the non-speaking members at the Bad-Anon support group. Sonic and Eggman have both appeared in two arcade games: SegaSonic the Hedgehog, released only in Japan, and Sonic the Fighters. Interestingly, these games feature Sonic and Eggman (called Robotnik back in those days) in their classic styled look, while Wreck-it Ralph features them by their most current style. These forms of Eggman and Sonic have never been anywhere near an arcade, so what they're doing in the Wreck-it Ralph universe is a bit of a mystery.
Just for comparison, here's what Sonic and Eggman (or, Robotnik) should have looked like, and what they look like in the movie.
