I orignally wrote this.
Since people are encouraging me to rant on and on, I'll go into more depth. I should point out that Mr P's links to those videos astonished me, because I never realised people cared so much about it, I thought, like "Eyes Wide Shut" most people did not think it one of Kubrick's classics (fools on both counts.) IKubrick seems to have made a movie which on the face of it seems like a dark farce (something I think all his later movies share) From Jack's daffy duck performance to Shelley's clothing and mannerisms being reflections of goofy (cartoon characters appear a lot in the movie) the whole thing has an air of the absurd about it, even down to the big teddy bear with the eyes that are mirror images of the dials above the bloody elevator. But beneath the overtly cartoonish aspect there are several things going on that I think Kubrick did deliberately to disturb the viewer, without them being conciously aware of it. For example the dead children appear in a corridor that is never seen in the hotel no matter how many times Kubrick maps the place out. The scene with Jack an the zombie chick in the bathtub seems to not be real but a vision of Danny's and of course there is the proliferating and disappearing photographs as well as the moving chairs(in many scenes including the dead girls scene and the bloody elevator) and entrance to the maze moving from the front of the building to the side. Some people have suggested such things are continuity errors. If so there are a lot, too many in fact for someone as obsessive about image as Kubrick I'd say.
There's the whole subtext of the hotel being a place for the elite, placed on an indian burial ground and Jack always being the "muderous" caretaker. This monster character sets about trying to kill a woman and a child and succeeds in killing a black man (a nigger cook as O'Grady has it). In this sense it becomes a horror movie about colonialism and oppression (even having Jack talking about booze being White Man's Burden. Having recently read the Decline and Fall of the British Empire, one of the things that stood out was just how drunk off our asses we were). The hotel manager even mentions them living in the West Wing. I'm stopping because I could go on and on and on.
..and on.

Here is the original poster. Notice the blurred child has the eyes of the elevator dials.
Anyway let's start with the twins shall we? Apart from the "here's Johnny!" moment those two creepy little girls are probably the most well known part of the movie. "come and play with us. Come and play with us, forever and ever and ever." They say. This is directly echoed by Jack when Danny comes to see him and asks him if he likes it at the Overlook. "I wish we could stay here, forever and ever and ever." Says Jack cuddling his son. Is this coincidence or is it the voice of the Overlook? We know Danny is supposedly psychic so did Jack actually say that? I'm uncertain, but given the use of reflection and echo in the movie it is kind of creepy. Especially when you consider what Jack spends his time writing. "All work and no play makes Jack a dull boy."
Then there is Room 237, as I mentioned before this scene seems like some kind of dream sequence, one that is later echoed with Halloran. The soundtrack of thumping heartbeats and the cuts to Danny wide eyed and silently screaming suggests that something happened to HIM in room 237 as he claims. However in the scene it is Jack not Danny who sees the naked woman in the bath. It is only upon reflection in the mirror that he sees her as the grotesque which makes her "real" so to speak. Jack recoils in horror from this beautiful woman turned monster.
So did Jack see the same thing as Danny? I'm thinking no. I'm thinking if anything what we are seeing here is a projected trauma. We know that Jack hurts Danny prior to them going to the Overlook. Wendy's painfully desperate excuses to the doctor after "Toby" short circuits the kid early on in the movie make us think that it wasn't just an accident. That she claims proudly he's been sober for five months (I'll need to check that length, but I'm gonna watch it again for when I continue this properly) makes us think that the accident was recent, but when Jack is later talking to his reflection which has manifest as a barman in an empty ballroom (after he openly calls to sell his soul for a drink) he talks about injuring Danny three years ago. The guy has form.
If we look at the scene with Danny and Jack again he says at the very end of it. "You know I'd never do anything to hurt you." Is this a precursor to the abuse that then follows? Is Jack in there somewhere struggling with the very real demons inside him awoken by the hotel and his son's psychic ability that is amplifying it? Or is he just an abusive drunk who goes mad?
Or both?
More to follow.