Good article over at indieWIRE, where I'm Thinking of Ending Things author Iain Reid offers up his thoughts on Charlie's adaptation.

“It essentially touches on the same theme [but] in such a different way,” said Reid.

[...] Reid is loath to offer up his interpretation of the movie’s end, instead deferring to viewers and how they might read the conclusion. “I found it exhilarating to watch. I really appreciated what Charlie did. It’s ambiguous in in a different way that the book, [which] is ambiguous to a certain degree. And I’m just curious how people will interpret the end,” Reid said. (Source)