I feel Tony Leung Ka-fai is not convincing

Tony Leung Ka-fai as 李友林 has some moments that stayed in my mind. Many moments pass very fast, and I do not remember much after them. I do not hate it, but it did not pull me into the story. For me, it does not feel very real in many scenes. The role needs more detail, but the performance stays on the surface. Some emotions are too simple, and I cannot believe the character enough. This is only my personal view, but the performance changed how I enjoyed the film.