The movie, based on the popular book of the same name, is a return to a genre that Spielberg helped pioneer, which is why he says it made him nostalgic.
"I felt like I was a kid again making movies, actually the kind of movies I used to make in the '80s," he told ABC News. "I felt I was, not imitating that, but I felt like I was in that world again."
Furthermore, the acclaimed director said this movie gave him a very different experience than what he's used to when making blockbuster films.
"I felt like I was making this movie, not from behind the camera where I make a lot of my historical dramas, but I was making this movie in the audience with the audience as my collaborators, telling a story for the audience," Spielberg said.
In the world of "Ready Player One," reality is grim. But everyone can feel like they are escaping by entering The Oasis, a virtual reality program that lets users do anything and be anyone they want.
When The Oasis' inventor dies, he leaves behind a challenge: Whoever solves the puzzles he's embedded in the program will inherit it.
When the hero, Wade, played by Tye Sheridan, joins the quest, he gets way more than he bargained for.
Spielberg says filming a movie set in a VR program allowed him to stage incredible scenes, but there were pros and cons. Take car chases, for example.
"The virtual world car chase was a heck of a lot safer than if I had tried to create those exact shots with those exact stunts in the real world," said Spielberg. "But I think it would probably be a little less expensive shooting a real car chase...It cost more to do that digitally."
"Ready Player One" is out in theaters nationwide today.