These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
In Amityville 2, the evil spirit possesses one of the characters causing his head to swell up like a beach ball and make him let out a very Richard Simmons-esque scream.
The vast majority of the fourth movie, mostly due to the fact that the main threat is a tacky lamp. Special mention goes the the scene where it is implied the evil lamp drew with crayons on the walls, and the Sequel Hook that consists of an incredibly cheap-looking PhotoShop effect making the cat's eyes glow a cartoonish red.
Fridge Horror: The implication that the events in Amityville 1992 had happened more than a few times before Andrea finally destroyed the cursed clock because she was able to retain her memories this time.
Since The Amityville Curse didn't take place in the titular Amityville house, the name itself seems to imply that there is something wrong with Amityville itself which is why there's been more than one home that's haunted and possessed.
Newer Than They Think: This movie started the whole "houses built on Indian burial grounds will be haunted" thing.
Sequelitis: Series descended into it after the second movie.
Surprisingly Improved Sequel: While it's lower-budget and far sleazier than the original, many horror fans consider Amityville II: The Possession to be this; it's faster-paced and scarier than the first film, which many find boring.
Amityville 1992: It's About Time is considered the best of the direct-to-video sequels, and far superior to the two that preceded it. Many even find it better than the theatrically-released Amityville 3-D.