https://nwhyte.livejournal.com/3093984.html

I think this is the only work of poetry adapted to become an Oscar-winning film - Glory For Me was MacKinlay Kantor's 276-page blank verse response to Sam Goldwyn's commission for the screenplay that became The Best Days of our Lives. The second paragraph of the third section, reflecting Fred Derry's experience, is:

(It’s hard to think that you are young when you are seventeen.
It’s hard to think that you could ever be just seventeen,
When you look back from twenty-one,
And know that you have killed a hundred men or more.)

The biggest change made for the screen is that the original Homer had PTSD and brain damage affecting the motor system on one side of his body; when Russell appeared on the scene, the character's disability was changed to the physical loss of his hands. Having said that, the character arc is pretty similar, though more dramatic, with Homer attempting suicide with Fred's gun and Wilma then talking him round to continued life, with her support.

She held the book
Squeezed precious in her hands.
“About a man ... he used to be like you.
He wrote this book himself—a man named Carlson.
And I’ve read Helen Keller, too. But Carlson knows
Just how it feels to be like you,
And worse. He crawled around;
He couldn’t walk, and he was born that way.
That’s how he got the title for his book,
He calls it ‘Born That Way.’ You see,
It’s better, Homer, if it happens to you late:
You have a pattern formed. He says
You have to re-establish it—the pattern.
All the motions that you make,
You have to will them—think them out.
And you can do it, Homer. Yes, you can.”

In general the poem has more drama (perhaps even more plot), though one early and significant divergence is that Fred and Marie decide their marriage is over the night he gets back, rather than trying to make a go of it as they do for most of the film. He is far from blameless - he has had several love affairs during the war, including one with an aristocratic Englishwoman, and he hits Marie when he discovers that she has been doing the same.

“You file for the divorce,” he said.
“It’s easy in this State. I socked you:
That’s enough. But don’t you spend too much.
Look—here’s a hundred bucks—”
He brought some money out
And counted off five Twenties.
“That’ll be enough.
It’s all you’ll get from me. No alimony, babe.
And do it quick. And if you don’t
I’ll go myself, and file, and tell
Just what I found when I came back—”

And Fred and Peggy get somewhat better closure than on screen (in that they definitely bonk, but in a poetic way).

The poetic form allows Kantor to sum up the point of the story with a vivid metaphor, much more so than is possible on screen:

WHEN YOU come out of War to quiet streets
You lug your War along with you.
You walk a snail-path. On your back you carry it—
A scaly load that makes your shoulders raw;
And not a hand can ever lift the shell
That cuts your hide. You only wear it off yourself—
Look up one day, and vaguely see it gone.
You do not see yourself in malformation.

The men and girls who have no shells
Of War upon their backs—You count them well deformed.
You recognize the other snails by eyes or ribbons;
You speak your perfect language to their ears,
And they to yours. You look with solemn eye
On those without a shell. You do not scorn,
You do not hate, you do not love them for it.
You only say, “They have no shell.”

With other snails you crawl the quiet street
And wonder why you’re there,
And think of folks who aren’t.
You polish up your shell for pride
Until you tire of it.
And one day it is gone if you are wise. ( )