I was really impressed with this mate. I thought the writing was really beautifully done. Yeah, it's an adaptation and I haven't read the short story, so it's difficult to comment on it. I've written a short adaptation before and have been working on a feature length one, so I know that it is a hard thing to do. It certainly isn't a case of just copying from novel to script-format.
What you do need to be aware of is the sort of words that are basically just redundant in scripts. Certain phrases that are nice and poetic in a novel or short story but in a script is just wasted space.
It would be interesting to read the short-story, because what impressed me almost as much as the dialogue was the visuals you created. I thought they were really well done, and I doubt that you were able to get them from King's book. I'm guessing these are the visuals that came into your head while reading and you put them in. That's a hard thing to do, so, again, really well done with them.
I especially liked the end, dream sequence. I thought that was a really nice, but haunting, way to finish off.
Well done with it mate and sorry if my notes above were messy. They were literally just jotted down as I read.