Riddled with spoilers, obviously.
The Haunting. Everybody in this game (Call Of Cthulhu) has heard of it. 99.999% have either played or run it or both, in various guises and incarnations it's been around since the first edition of CoC.
And maybe this is the problem. At least for me, it feels a bit dated and like it's been designed to showcase different elements of the system but not cohesively. And it's almost pointless in it's outcome. And it's certainly not a good introductory scenario. But, a step back and let's start at the beginning.
The setting is obviously a classic of horror, and even Lovecraftian horror has a lot of time for a haunted house (The Lurker At The Threshold, The Rats in The Walls -which could have made a fantastic base for this scenario imo- et al.). So it obviously isn't an inherently bad setting. However, translating this into a game setting means getting rid of a couple of tropes that will severely hinder the creepiness of this scene. For starters, a team of investigators negates much of the paranoia present when a lone stranger investigates the creepy house. Dominate is able to offset this to a certain extent, but once they learn to slap any other player who goes glaze-eyed and comes towards them, the fun with that becomes limited. Now admittedly many players will split up, which is a perfect time to reintroduce the horror, but they don't have to. I think a key part of the creepiness, especially in something as well trodden as this scenario is to force the players into uncomfortable situations. About the only real opportunity for this is to dump hundreds of bloodless rats on a player if they investigate the oozing walls. The bed has never, ever been more than a comic element in my running and reading of this scenario. If someone else can make this genuinely horrifying then hats off to you.
Now, to explain my feelings on the disjointedness of the scenario. As I see it, there are three specific sections of the scenario.
1) The house itself, investigation, discovery and fighting thereof etc.
2) Discovery of the events leading up to the Macarios' institutionalisation and the interviews with family and neighbours etc. (Current events as it were.)
3) Research of the history of the house and the links to the Occult and the Chapel.
Correct me if I'm wrong, but the last two sections are entirely superfluous... It is not necessary to talk to the Macarios at all, except to perhaps get a little preparation for the poltergeist activities. Believe me, I really like the backstory to this scenario too, with Corbitt's links to a local cult and his own experiments. But it just leads me to a general conclusion of 'So what?'. It's not useful to the players, it provides no information on the defeat of Walter and even the history of the house reveals nothing that looking at the fake wall intently enough won't. It all smacks strongly of old style D&D etc. dungeon-crawlers where you attack the Designated Villain because it's what he's there for.
Mr Corbitt himself is a rather strange villain. He doesn't really seem to have a motive for mischief making, he only works inside the house, and only when there are others there. He's not moving toward some other nefarious purpose, he just wants to be left alone. That's not cosmic horror, that's an old guy shouting "Get off my lawn!". As such, you can raze the house or similar and not have much repercussions, as he'll just lie in his chapel and stay there. This doesn't strike me as being right somehow. So there's that. I guess you can find some consolation in having removed the source of the family's madness, but if you did that by just throwing a Molotov in and running away, that's hardly very impressive is it? And certainly not justifiable in the eyes of the law...
Which brings me to my next point. This is not suitable for beginners. If anything, I would recommend it for more world-weary groups who are expecting a cult and conspiracy behind every corner. For a start, it sets a false precedent. The baddie is entirely corporeal, defeatable and requires little magic or even SAN loss to deal with. THAT IS NOT HOW ANY OTHER (well) WRITTEN SCENARIO WORKS. So it seems silly. It also de-emphasises research. Now I have a hard enough time convincing my players that no good can come of running in full tilt as it is, without this as well.