Mahershala made me believe his three different ages in the first 2 episodes. I wasn't sure how it was going to be seeing him at "3 ages" constantly, but each has their own little things that really make them believable for me. His "confusion and longing to remember" was very prevalent in his eyes throughout the episodes, and I enjoy the style of story they have started. The past is all in memory form and it shows how Wayne Hays is working through the story in his memory. I enjoyed the few times they were in the "past" and it snapped to reality, like with an elder Hays saying "I don't want to be here" talking about the "Trash Man"s home but in reality he was saying it in real time. You can tell he is working through some difficult memories, and as they come back you can see his aging mind work.
I'm very optimistic about this season after what we've seen. They story is set up to be suspenseful and a lot of little tid bits can lead us to a numerous suspects (a lot of the tid-bits are surely decoys). The hole in Will's room, the Trash Man and Wayne saying "well, you know what happened to him.", the dolls and halloween, the "Black Sabbath" comment, etc.
Should be fun to watch them untangle this knot.