One of the bonus features on the Ready Player One Blu-ray release has a cool Back to the Future reference. Early on in the film's marketing campaign, Warner Bros. billed the movie on being a pop culture phenomenon, with Easter eggs and references to virtually every property out there - and they caught some flak for that. Many people who weren't familiar with Ernest Cline's 2011 novel of the same name had no idea what to expect from the feature film adaptation.

The Ready Player One teaser trailer from last year's Comic-Con International referred to the film as an adaptation of Cline's "Holy Grail of Pop Culture," instead of spending more time to highlight the story behind the movie (and the book, for that matter). And while the final product did emphasize that story, that doesn't mean a lot of time wasn't spent on Easter eggs and references. Considering how many avatars are onscreen in the final battle on Planet Doom, it would take a long time to identify each and every character. So, while Ready Player One ended up being more than just a references-filled movie, there were still plenty of Easter eggs to look out for - and the home video release is no different.

Related: Ready Player One Took Eight Years To Make

In one of the special features on the Ready Player One Blu-ray, Ernest Cline briefly talks about the book's fans being concerned with the movie adaptation, and, in discussing the matter, he makes a noticeable reference to the Back to the Future movie: "...And when fans of the book ask me about it, I just tell them that they don't need to worry. That I haven't worried since the day that Steven Spielberg signed on to make the movie. I tell people, it's like density. It's like meant to be."

What Cline is referring to is a scene from Robert Zemeckis' first Back to the Future movie from 1985, in which Crispin Glover's George McFly walks up to Lea Thompson's Lorraine Baines inside Lou's Cafe and accidentally tells her that he is her "density" instead of destiny. The actual quote is, "Yes. Yes. I'm George. George McFly. I'm your density. I mean, your destiny." It's a small reference, but a clear one at that considering Cline smirked when he said it. With over 90 minutes of bonus content on the Blu-ray, it can't be the only reference on there, let alone the only Back to the Future reference.

Zemeckis' Back to the Future trilogy played an integral role in the Ready Player One book as well as the movie. For instance, in one key scene in the film, Parzival (Tye Sheridan) uses the Zemeckis Cube to turn back time by 60 seconds so that he and Art3mis (Olivia Cooke) could escape The Distracted Globe dance club. But the most notable influence came in the type of car Wade Watts drove in the game: a DeLorean DMC, one that had been customized to look exactly like the one in Zemeckis' film trilogy.

More: Everything We Learned From The Ready Player One Blu-ray

Ready Player One is now available on Blu-ray and digital HD.