It was not so much that Wade and company were supposed to go to the theatre where Halliday watched the Shining (as the Shining was a movie Halliday rented), but that the Shining in the Oasis represented a location where they needed to go to look for an easter egg that Halliday had hidden...

>! The second task, for the Jade Key, comes from a clue at the end of the race, alluding to a "creator that hates his creation" and "leap not taken". Parzival and Art3mis try various permutations of this building from what they perceive to be Halliday's biggest regret - his failed date with Kira Underwood, later Ogden's wife, and - after their real-world flirtations hit a pause - realize it's in the movie Halliday and Kira watched when she wanted to go dancing: The Shining, a film author Stephen King famously despised. The following sequence is, by the film's own admission, a distraction, with the real solution being asking a program of Kira to dance. Aside from the level of knowledge required to solve the clue - any gunter must have an intimate understanding of Halliday's life (Kira was only mentioned once in the archives) and Stanley Kubrick's filmography - this shows to the players how to learn from prior mistakes.

This whole answer along with more information about the other easter eggs can be found on [ScreenRant][1], described by Alex Leadbetter.

There is also more detail about the whole Shining scene on the [same website][2], by Padraig Cotter.


  [1]: https://screenrant.com/ready-player-one-movie-ending-easter-egg-explained/
  [2]: https://screenrant.com/ready-player-one-shining-scene-explained/