I haven't read the novel but maybe what worked on the page as an allegory didn't translate well to the screen. I thought The Long Walk was the most implausible genre film I've seen since A Quiet Place. The premise didn't make sense at all (even in this dystopia, would anyone take part considering the odds?) and neither did the way the characters acted in these circumstances (why wouldn't the participants at least prepare for this?)
I did, however, enjoy the prequel series It: Welcome to Derry. Also conceived and partially directed by Andy Muschietti, it's on a par with the first of his two films, which I liked. (I have no sentimental attachment to the '80s miniseries.) By the sequel, it became clear that splitting the films into past and present was a mistake, as the contemporary story is much weaker than the part set in the past. However, the series moves even further into the past, and I found this genuinely creepy.