So Marven is the biggest bomb of Zemeckis' career

... quite true. But the film offers quite a bit of darkness and despair, and its failure to meet the expectations of critics and viewers (which is not a bad thing) probably accounts for most of the negative reaction. 

i spent 15 minutes writing a post and lost it because I double clicked and the window closed itself. I spent 30 minutes rewriting it AND adding more information and when I clicked post reply I got an error msg and the post disappeared. so. yeah. now i am going to go scream into a pillow and the world will never know why this movie is so troubled or what they should have done better :]

I viewed Welcome to Marwen a second time almost two weeks ago, and that viewing confirmed my original opinion: I deem the movie "very good," probably one of 2018's ten best, and better than any of the movies nominated for Best Picture by the Academy this year. I find Welcome to Marwen exceptionally engrossing and very vivid, both visually and emotionally. Here are a few specific observations that I took away from my second screening:

*The movie is quite impressive visually, offering some graceful and unpretentious long tracking shots as well as fairly nuanced lighting. A couple of scenes stand out to me for how effectively director Robert Zemeckis complements the material visually. When Nichol knocks on Mark's door to bring him a pair of stilettos, she is wearing a floral dress, but Zemeckis shoots this scene with a rainy, misty, overcast background, giving those vibrant colors a slightly pale and faded look, as if the occasion is not as festive and gratifying as it should be. Indeed, in this scene, the audience witnesses the first moment of doubt regarding the nature of Nicol and Mark's relationship.
In the film's pivotal scene, when More directors would have milked such a crucial and intimate scene in closeups, but Zemeckis switches from close coverage to sustained deep coverage, and the effect is unforgettable. 

*What people are calling "creepy" would be, to me, "quirky." I certainly do not believe that Carell's Hogancamp is a "creep," but the film does not shy away from his eccentricity or force him to conform to the conventions of a sentimental fable. 

*Again, I would not say that Mark "mistreats" Roberta. Rather, he seems reluctant to become involved, and this reticence can be easily explained by his alter-ego, G.I. Hogancamp. Mark's doll does not want to become romantically involved with anyone for fear of being hurt, and he is essentially speaking for Mark in that regard. Of course, Mark—unlike his doll—actively pursues Nichol, but she is his fantasy, and for her he sheds his romantic reluctance. But for anyone else, Roberta included, there needs to be a gradual process of realization and maturation, and the film's narrative serves as Mark's process. 

*Upon my second screening, I fully recognized that Roberta has a doll of her own, and Hogancamp often renders her (doll) topless. As Roberta pointedly asks early in the movie, "Where's my top? Where's my top?" And Mark replies, "Oh, you know, the Nazis." "Again?" asks Roberta. 

Repeatedly rendering Roberta's doll topless seems to be a form of foreshadowing, indicating that Mark does—or will—possess romantic interest in her. He just does not know it yet, or he is unwilling to acknowledge that interest for most of the film.

*Zemeckis does a wonderful job with his musical selections, offering somewhat eclectic samples of rock-and-roll or rhythm-and-blues and using those songs in a sparing, sporadic manner that increases the impact of certain scenes. Conversely, most of the film's scenes involving human interaction feature no music whatsoever, a decision that enhances their intimacy, sensitivity, and emotional authenticity. Again, many filmmakers could stand to learn from this choice. 

*The film offers some oblique criticism of the war in Iraq, which is unexpected for a fable yet offers some refreshing relevance. 

*On the second occasion, I attended Welcome to Marwen with someone else. Afterwards, she called the film "the strangest movie I have ever seen." But she said that after becoming acclimated to the technical style (she initially did not know what to make of the movie's visual strategy, not understanding if it was an animated feature or what), she really liked it. She thought that the filmmakers managed the visual blend expertly, and she agreed about the film's intimacy, soulfulness, and social relevance. She asked if it had received any Golden Globe nominations, and when I told her about the film's unfortunate critical reception and commercial failure, she replied, "Shame." 

*Universal ultimately made a major mistake by releasing Welcome to Marwen in the Christmas season. Yes, it is a sentimental fable that could be uplifting in the holiday spirit, but the film is quirky, somewhat dark, and nuanced. It does not follow commercial convention—it is certainly not a Hallmark movie—and it would have been a better choice for a quieter movie month (say, April or October) where people would not have been as focused on its commerce. 

Well he still got paid a lot of money to make it so he can cry all the way to the bank.