The Dark Half is one of the most well-adapted King stories ever put to film, and I think that's owed mostly to the friendship between Stephen King and George Romero. However, some things don't always translate well from page to screen, even if it's a solid adaptation. I saw that in Pet Sematary, I saw it in Thinner, and I definitely saw it in The Dark Half. It's not a bad movie, it just doesn't have a lot of punch. You never really feel the gravity of the situation like you do in the book, and that's mostly because we're constantly in Thad Beaumont's head. We're along for the ride as he battles his manifested dark twin George Stark. In the film, it's more like we're a witness.
Timothy Hutton plays both writer Thad Beaumont and his pure evil pen name George Stark. Hutton delivers a fantastic performance and really makes both of these characters stand out. The rest of the cast is pretty bland, and I think Michael Rooker was miscast as Sheriff Alan Pangborn. I pictured a much older, more reasonable man. In the film, Pangborn has it out for Thad from the start and never wavers in his opinion. Also, he's mostly absent from the ending and never gets to have the confrontation with Stark that was in the book. I thought the murder scenes were done well, and I'm glad Romero kept the sparrows.
The Dark Half is one King story that I think could benefit from a remake with an up-and-coming horror director like Ari Aster or Robert Eggers. It's a very cerebral story that's more about identity than horror. Romero did a decent job, but it could definitely be done better.