As everyone already knows, Hemingway is terse. He doesn't give his sentences any more room to breathe than they absolutely need. He's like Raymond Chandler in that respect; yet, simultaneously, not like him. Chandler wrote "hard" prose because it was easy to understand and created an atmosphere of masculine forthrightness. Hemingway had deeper artistic reasons. When it works, Hemingway's prose captures an emotion precisely because it does not try to articulate it. This line (which maybe doesn't work outside of context) is a good example:

"The water was clear out there and there was a spar of some kind sticking out just above the water and when I came up close to it I saw it was all dark under water like a long shadow and I came right over it and there under water was a liner, just lying there all underwater as big as the whole world." [from "After The Storm"]

There are writers, writers I love, who would fill up a whole page with description of a sunken ocean liner. This is the instinct of every writer, or at least the thing that gets drilled into us in every creative writing class. Be more specific. Use more concrete detail. But can we really be sure all of that detail does as much for the reader as Hemingway's simple, and immensely forceful, declaration: "as big as the whole world"? I don't think we can. That's what makes Hemingway's writing kind of spooky; he was able to do so much with so little.