The film's main character is the bad guy in a video game who wants a shot to be a hero for a change. So, inside the video arcade he calls home, he game-jumps in an attempt to make that happen.
The movie is about his journey and the characters he meets along the way.
Reilly, the voice of "Wreck-It Ralph," sais he was a video-game buff as a kid.
"I was also of that same generation. I remember when it went from pinball machines to Space Invaders. It was like, 'What? How do I get more money?'" Reilly said.
Reilly said Ralph's story is, in some ways, the story of a mid-life crisis - which makes the film relatable to a wide age range.
In addition to a storyline that reaches older audiences, there are also plenty of jokes in the film that will go over kids' heads. For example, kids may not get the Bad-Anon meeting of video villains.
"I think they just try to tell an honest story, a true story, and this hero's journey of this guy trying to find himself and accept himself," said Reilly.
Reilly was happy to accept the "Wreck-It Ralph" role and to be included in the creative process along the way, even helping in creating his character.
"I've been in the business now for quite a few years and you learn at some point it's great to have older people that are into you as an actor, but who you really need, if you want to keep working, are those younger people," said Reilly.
"Wreck-It Ralph" is rated PG.