What are two poetic devices presented in the poem "Richard Cory," that helped to enhance the poet's work.

Here's the poem:

Whenever Richard Cory went down town, 
We people on the pavement looked at him: 
He was a gentleman from sole to crown, 
Clean-favoured and imperially slim. 

And he was always quietly arrayed, 
And he was always human when he talked; 
But still he fluttered pulses when he said, 
"Good Morning!" and he glittered when he walked. 

And he was rich, yes, richer than a king, 
And admirably schooled in every grace: 
In fine -- we thought that he was everything 
To make us wish that we were in his place. 

So on we worked and waited for the light, 
And went without the meat and cursed the bread, 
And Richard Cory, one calm summer night, 
Went home and put a bullet in his head.

Henry David Thoreau said "men live lives of quiet desperation."  None more than Richard Cory, it seems, whose suicide is not necessarily a shock to those in the town, but rather a source of morbid fascination and gossip.

The poem appears simple, straightforward, and conventional: there is no metaphor, no simile, no symbolism, no lyric self-expression.

Rather, the key is the speaker's tone: he is a reporter giving us the news.  The poem reads like an obituary.  It confirms what all the townspeople already know, but it seals Cory's death in black and white print for posterity--a detached epitaph for the ages.

The two key poetic devices are irony and humor which relies on the contrast between the image of Cory's stoic exterior  and the violence of his death.  If a longer piece, the poem would be Horatian satire, black comedy.

Critic Ellsworth Barnard says it best:

The first two lines suggest Richard Cory's distinction, his separation from ordinary folk. The second two tell what it is in his natural appearance that sets him off. The next two mention the habitual demeanor that elevates him still more in men's regard: his apparent lack of vanity, his rejection of the eminence that his fellows would accord him. At the beginning of the third stanza, "rich" might seem to be an anticlimax—but not inthe eyes of ordinary Americans; though, as the second line indicates, they would not like to have it thought that in their eyes wealth is everything. The last two lines of the stanza record a total impression of a life that perfectly realizes the dream that most men have of an ideal existence; while the first two lines of the last stanza bring us back with bitter emphasis to the poem's beginning, and the impassable gulf, for most people—but not, they think, for Richard Cory—between dream and fact. Thus the first fourteen lines are a painstaking preparation for the last two, with their stunning overturn of the popular belief.