This is by far the best episode in Castle Rock (so far). I don't have much to say about The Box because it's a near-perfect episode. The tension built from the opening scene and kept rising till just before the credits roll. The Box is also the most though-provoking episode, so far. I couldn't help but keep thinking and trying to solve this well-crafted mystery. The character of Dennis is creepy and its development is high-class, and Noel Fisher delivered a terrific performance in this role, particularly in this episode. The acting, in general, in The Box is at its peak, and from every actor/actress involved. Sissy Spacek also shines in this episode, as she, finally, had a chance in one scene to show her acting abilities.
Even the music has been utilized very well in this episode. Just some moments of " I've seen that before" that kept me from giving this episode ten out of ten, along with one single uninteresting and unnecessary scene.
(9/10)