The Beyond is clearly among the best horror movies ever made. I do not remember where I read it, but I read a critical exposition of this movie and it called it an absolute movie. What on earth does "absolute movie" mean? According to the explanation, it means that the film is basically just a sequence, or succession, of images. The storyline is completely secondary in such movies.
Like many people have said, it is true that this movie has very little plot development: A strange, occultist painter was crucified in a certain cursed hotel, opening a gateway to hell and allowing evil, and the living dead, to enter the world. That is it. However, The Beyond is a very beautifully shot movie, and it has one of those fantastic musical scores that the Fulci films are often famous for. It is very good indeed!
I regard The Beyond as one of Fulci's best works and like I said earlier, as one of the greatest horror films that anybody has ever made. I very much like Fulci's dry approach here: like in Zombi 2 and City of the Living Dead, there is zero humour in this movie. That is the way it should be, because horror is supposed to be horrible, and there is no room for comedy in those works of art.
Quentin Tarantino organized a theatrical re-release of The Beyond in USA in 1998. A special tin-can DVD box set with numerous extras was also released at the same time. I actually have two of the biggest Italian original posters of L'Aldila, but I am now too lazy to dig them out of the closet and take photos. Sorry about that, but trust me, they are magnificent.
In my review of Lo Squartatore di New York (1982), I mentioned that Tarantino had seen that movie 25 times. Despite that, he chose The Beyond for the re-release in the USA, so I guess it is safe to assume that Tarantino has seen it well over 20 times, too. It is now January 14th, 2019, and I actually also would like to see The Beyond again. Yesterday I watched some Fulci trailers on YouTube and they are certainly good and tempt you to see the films.
The mood in The Beyond is almost surreal and there is enough nasty violence to keep horror fans happy. Back in the 1980s, I only could see a bad quality VHS video copy with Swedish subtitles, so we should be thankful for the great, crisp blu-ray editions that we now have. In conclusion, this film is a must for all horror fans. It is a horror masterpiece, I have no doubt about that!