Sir Arthur Clarke says in his Collected Stories that he worked on this script, not (as the on-screen credits and IMDb would have it) that he wrote it entirely himself, based on his short story. The Americanization is pretty heavy, and removes what subtlety there is in the original characterization. The plot hole in the Goofs section, though, is present in the original; though it's not certain that it _is_ a hole—we're not told in the original what would happen if the protagonist violated the prohibition.
One nice touch new in the screenplay is the newspaper in the opening scene.
One nice touch new in the screenplay is the newspaper in the opening scene.