Can anyone give me feedback on this descriptive writing

Alone. The old man sits on his rocking chair perusing The Daily Mail. He looked up, his azure eyes transparent as the cloudless sky, staring soullessly out to the barren moor. His pale face with deep wrinkles, his eyebrows grey and bushy, his hair winter white stuck on to his head like wisps of string. His body decrepit, frail with a hunchbacked posture got up unsteadily, seamlessly shaking with assistance of his wooden walking stick, plodding with every step.

Taking out a collection of photos out his chest pocket as he sat down on his narrow bed, he stared; his mind turned like rusty cogs within his brain, surging with memories of the distant past. A man uniformed in an elegant military green in the photo serving his country, reminded by when the gunshots were fired, the bullets flew as if in slow motion like a whistle in the air. Cannons that break its moorings suddenly becomes a strange, supernatural beast, exploding with fury upon the battlegrounds. Terror became a familiar stranger.

The feeling of the clammy trenches, sleeping shoulder to shoulder, hearing the planes that fly above, bombs which explode in the far distance. Rats, beady eyed, ring tailed and as big as cats, waddled past with their bounty, heedless of the men, feasting ravenously upon the dead bodies. Faeces and urine, the foul smell which rises upon the air, spreading towards the soldiers from miles away.

Trauma. Bullets that relentlessly shot through his neck, pounding through like a heavy weight boxer. Blood peppered the ground beneath him. A solitary tear ran down his cheek which was shining in glory. Seeing the scar in the mirror everyday reminded him of the times of agony and pain, an everlasting stain. Something he will never forget.

That's quite a good story for starters, but I'll recommend reading novels by John Grisham or James Patterson to improve the structure of your writing a little bit.

The descriptive language is good. The change in tense between paragraph one and paragraph two is a bit confusing though, and I don't think I would have done that myself.

What did the question ask you to describe, out of interest?

What grade would you give it?

Write a description of an old man