I dunno. Supernatural horror is clearly my favorite movie/series genre, and certainly people seem to be really enjoying MARIANNE. At the time of writing this review, only 14 of the 41 extant reviews were 6/10 or less. Everything else was 7/10 or better, although you do have to discount that a little due to the presence of shill reviews.
With apologies to Douglas Adams, I didn't even get to the point of worrying about MARIANNE's fundamental flaws because they were so thoroughly concealed by its superficial flaws. Personally, I would rename MARIANNE to STORY LAPSE.
Even putting the innate supernatural horror story special complexities aside, and as I have written so many times previously, making a movie or television series of any kind is an INCREDIBLY difficult and intrinsically error-prone endeavor. It's basically creating your own world for the purposes of filming it. Inevitably, even with the best, most professional, most expensive effort SOME errors are going to creep in.
But it's all a matter of degree. If the errors are few and far between, you just overlook them as a tiny price to pay for some great entertainment.
But when the number of errors and story lapses build up into a giant pile, it tends to obscure everything else about the program. You can't see the forest for the trees and you can't enjoy the program for all the examples of poor workmanship and continuity errors.
I know, reviews that are of the nature of a "all-the-things-wrong-with..." diatribe are the dullest reviews of all, but what to do? If you sit through an entire series and that's the primary impression you come away with, well, then, as a reviewer, you're sort of stuck. In your review, you write about what stood out to you.
So...
1. The entire show had a sort of Thomas Pynchon stream-of-consciousness feel to it rather than a logical, reasonable progression. Stuff just happens.
2. There are a few, repetitive, nursery-rhyme-like quotations having to do with the history of the eponymous MARIANNE, one of which is that she was buried "5 feet down". And yet every time we see her open grave, it's clearly more than 5 feet down. Not a huge deal, but if you're going to pound that into the audience repeatedly you should at least consider this point a continuity detail when you're making the show.
3. A plot detail is that, when our main characters were teenagers going to school, their school was a combination schoolhouse and lighthouse just a little ways off shore and connected to the mainland by a roadway that is underwater during high tide and to which they were bussed every school day. Important plot points during the present day and in the character's pasts occur at this location. Of course, there is absolutely NO POSSIBLE WAY that such an arrangement would EVER work given the fact that the cycle of tides walk around the hours of the day and night over time. Nothing like a regular class schedule could EVER be kept because EVERYTHING would be dominated by what the tides were doing and controlling when the students could come or go. It would be literally impossible to run a school under these circumstances.
4. When Emma is a teenager, an irritating little girl and younger sister of one of Emma's friends, Lucy, has the habit of grabbing people's phones and running off to hide to kind of force people into playing hide and seek with her. Finally she engages in this stupid behavior just once too often and gets herself killed in the process. For obvious fear and other emotional reasons, Emma never mentions the fact to anyone that it was Emma that Lucy was plaguing with this behavior when this happened. But of course, Lucy had Emma's cell phone in her hands when she died and everyone should have concluded that Lucy was engaging in her hide and seek behavior when this happened since there would have been no other reason for her to hide. So everyone should have known that SOMEBODY had been present when it happened. If Emma ever calculatedly pried her cell phone out of Lucy's cold, dead fingers to conceal her own presence and then walked off, certainly WE were never shown this. That takes the entire episode out of "got scared and ran away" to "carefully calculated how to protect myself".
5. Emma, the primary character for the entire program, is characterized as utterly self-centered. As we find out near the end, the actual TRUTH is that she sacrificed the life she knew and burned every relationship bridge she cared about in order to protect her parents and her friends. This she did on the advice of the local priest. Ultimately, in the end, this strategy completely fails AND she never mentions this fact to ANYONE through the entire show, even when the ploy has failed at the beginning of the show and even though the same priest is still around to corroborate her story. Even at the end of the show, what friends Emma has left are still operating under the idea that she's an utter, self-centered beeyotch. Who on earth would ever behave that way? Who would let the world think that they were a terrible person far past whenever doing so would do anyone any good?
6. The mechanics of the story is that this evil witch from the past possesses people and uses them to do more evil. The first character she inhabits, Mrs. Daugeron, is charged with murder because of her behavior while possessed, and even though Inspector Rauman himself becomes fully aware of what's going on, Mrs. Daugeron is apparently just left to rot with these charges against her.
7. Over and over again during the entire program, there's this hole in the ground about a foot and 1/2 across with perfectly vertical sides as if dug by a post hole digger; I'll leave it to you to discover the reasons for this hole for yourself. In the last episode this hole is covered by a small, heavily weatherbeaten shed which has, by the looks of it, been there for some time. Emma pushes the shed over to get at the hole. Have you ever left a car parked in a single place for a long time or a piece of plywood on the ground for any length of time? When you move your car or you lift up whatever you left on the ground, the most you'll find there is rotting detritus and a few pill bugs. And yet, when Emma pushes the shed over, NOTHING distinguishes the area that had been under the shed from everywhere else in the vicinity, INCLUDING the perfectly healthy, very green grass. In fact, there was nothing to suggest that the shed had been there at all.
8. In some of the final scenes at the end of the program, Marianne, the titular witch, costumed in her period, black, heavily panniered dress, is walking along the cliffside shoreline in spirit with the spirit of Emma. On a small rock island off the shore of the town, there are 2 or 3 crosses that we have seen several times during the show. Except somebody got the scale wrong in the special-effects crew. As depicted, they would have to be at least 20 stories tall and possibly larger, completely out of scale with everything else.
This is only a smattering of the continuity and workmanship errors in the show. I know, my laundry list is tedious and dull, but it serves to support my position that the show made so many errors that the overall production suffered badly. There were lots of jump scares and some frightening visuals, but the quality of workmanship was really a mess. Quality supernatural horror requires a tight rope balancing act involving breaking the rules of reality to just the right extent and keeping everything tightly held together in the process. In the end, MARIANNE devolves into scary images thrown at the screen nearly at random with the apparent hope that you will be covering your eyes often enough to overlook the innate sloppiness of the entire program.
Details aren't irrelevant. They're the canvas upon which the whole story is painted. Ignore them at your peril. Ignore them enough, as with MARIANNE, and you get laughter, boredom and irritation where you should be getting fear.