Watching the film again for the first time in a couple of years I was reminded of how much I liked the sense of ambiguity I was left with at the end. The film is obviously much more sympathetic to the family and Glover gives, as described above, a wonderful, devilishly charming performance throughout, often accompanied by threatening imagery.
As for his death, at first I thought Harry was intentionally stepping onto the marble in a last-ditch effort to win the family over again, and his death was poetic justice in full fruition. Now, however, I'm not sure what to make of it, I'll have to let it sit for a while.
I don't think it was intentional. It was foreshadowed pretty early on with the broom knocking over the bucket, and with the child touching Harry with the broom. I think there's a hopeful generational note here -- Harry is visibly uncomfortable around children. If you recall one of the many masterfully underplayed and chilling scenes when Harry has to sneak out of his room to avoid the child sweeping, its a bit more clear. The child next door with the trumpet also upsets Harry's attempt to hypnotize and slaughter the chicken.
Suzie: "Harry, one can sure tell you are from back home. Nowadays, people don't even know what good manners are"
Harry: "You had to know how to act right where we come from. You had to know when to say yes sir, no sir. You had to know your place."
Suzie:"That's right. In those days you could always find something redeemable in the very worst person."
Suzie: "Are you a friend, Harry?"
Harry: "Take that boy next door, playing his horn. If he was a friend, he would stop irritating people. But if he stops practicing, he wouldn't be perfect at what he does"
I think the whole film is captured in those two scenes quoted above. I especially like the "I have to know who is in my house"/"You invited me" exchange that takes place just before the second quote, which feels a little like it could come from a vampire film!
I think tartarlamb's description of the end is great, though I was also left with the feeling that it is sort of a sacrifice that the family (or more properly the children of the family in an unconscious manner, who despite that act as observers throughout, while the adults are too trapped in the material world to be able to properly understand Harry's influence) have to make to rid an 'evil spirit' from their house, which has been repressing the rest of the family (and the boy next door!*)
Yet it also feels as if the family are also using the 'temptation' that Glover's character represents to try and escape from the somewhat restrictive confines of domestic life (making it a kind of conterpoint to all of those films where a magical neighbour appears and expands a community's horizons - Michael, Hearts In Atlantis etc). Baby Brother is of course the major focus of this, maybe falling under Harry's unreligious, free spirit influence which inspires him to almost abandon his family, his wife and his son.
But there is also the idea that all of these issues were present long before Harry arrived, looking for an inspiration. While the film seems to be much more moving towards the way that Harry seems to be a malign influence, such as the way in the early part of the film he seems to be insidiously feeling out each of the family members for their particular weak points that can later be capitalised on, it also seems to be something within each family member that is responding to his presence as well. The father taking ill can be seen as another form of abdication of responsibility, albeit an unintended one, but also the way that Junior is inspired to become a rather unbalanced patriarch himself feels like the opposite extreme of being too controlling can lead to violence.
There's an obvious religious metaphor throughout and those scenes between Harry and Vonetta McGee's Pat (as someone who has previously had close ties with Harry but who after moving to L.A. has been 'saved') get the closest to a battle between 'good' and 'evil', though it never feels that simple, instead more as if they are taking on such roles partly playfully and partly with deadly seriousness in order to define who the other person is in their eyes.
All this actually makes me feel more for Harry than for any other character in the film - that he in some mysterious way ends up embodying everything that is going wrong inside that family into one easily disposable person. Everyone else is able to be saved, and gets a moral lesson in the path not
to take and a fresh start, but Harry was considered irredeemable from the start by almost everyone.
I was left thinking that this is also all tied up in questions of why the family (and a lot of family friends judging by the gatherings) made the move to L.A.? To escape their extended family which would have brought up similar tensions that Harry does, and to make a new start in a 'less respectful' L.A.? To keep the past on the mantlepiece, where it untroublingly belongs and move into a more successful, urbanised future? I suppose it is ironic therefore that it is only Harry's body which is occupying a doorway at the time of the earthquake near the end of the film (and I like the way that Harry is continually juxtaposed with that kitchen doorway throughout the film)
But of course the beauty of the film is that it always stays within the structure of a family drama, never taking that final turn into supernatural horror (for instance I particularly like the way that one of the brother's pregnant wives never has anything happen to the baby more than having it kick a couple of times when she first goes to shake Harry's hand, something which plays against conventional 'supernatural' expectations.)
*The boy next door, who triumphantly manages to play the trumpet over the end credits, which also seems to capture both points of view - he can finally play now that the 'evil, repressing spirit' is gone, yet he also validates Harry's talk of 'irritating until you become perfect at what you do'.