character interacting with others. A novel offers the possibility of exploring more than one fully rounded character, whose strengths and weaknesses can be minutely examined. It also allows for the possibility of creating a whole world of characters of different types and classes who can interact with each other and represent different points of views.

In summary, the length of a novel allows for more complexity, while a short story usually makes a single point.

It was Edgar Allan Poe who offered a definition of the short story which has been widely observed by authors ever since. In a review of Nathaniel Hawthorne's collection of stories and sketches Twice-Told Tales in Graham’s Magazine, May, 1842, Poe wrote:

A skilful literary artist has constructed a tale. If wise, he had not fashioned his thoughts to accommodate his incidents; but having conceived, with deliberate care, a certain unique or single effect to be wrought out, he then invents such incidents--he then combines such events as may best aid him in establishing this preconceived effect. If his very initial sentence tend not to the outbringing of this effect, then he has failed in his first step. In the whole composition there should be no word written, of which the tendency, direct or indirect, is not to the one pre-established design. 

A novel is not intended to produce a single effect because of its greater length than a short story. A short story is intended, as Poe established elsewhere, to be read at a single sitting. A novel is typically divided into chapters, and sometimes even into "books" or "volumes" because it is not intended to be read at a single sitting. Since a novel may be read in many sittings, each chapter can usually produce a separate effect. 

What Poe meant by the word "effect" is the feeling that is left with the reader at the end of the story. Poe maintained that every single word should be designed to produce that single emotional feeling. In some stories, such as those of O. Henry, the effect is usually produced by the ending. But there are many stories in which the effect is produced by the pervasive mood established from the beginning and sustained throughout. Edgar Allan Poe's stories "The Fall of the House of Usher" and "The Masque of the Red Death" might serve as examples of stories in which the single effect is produced by tone, mood, characterization, and setting. 

If a short story is intended to produce a single effect, then it would seem that a very good way in which to critique any short story would be to start by analyzing its single effect, i.e., the feeling the reader is left with at the end.

Their are perhaps several differences between short stories and novels, but length is probably the most obvious and least clarified of these differences. Obviously the short story is going t be shorter in length than the novel, but no one including writers and publishers have really established a length criteria. In addition, the novella must be considered between the short story and the novel, but here again there is no clear criteria on recognized length.

That being said, made their appearance as a result of oral tales being passed down through the ages being written down. So stories would logically be one of the oldest written genres. Stories have all of the elements of novels (or vice versa)--plot, characters, theme, setting, rising action, climax, falling action, and etc., and stories also use the same literary conventions that novels use. Although, all things considered, these will not be as developed, perhaps, as they might be in a novel. With the addition of "short-shorts" to the modern genres, stories take less time with development of character action and really zero in on character reaction.

Novels are longer, more developed, if you will, pieces of writing. An interesting development with regard to novels is the depiction of true life events into a fictional format. Truman Capote recognized his novel In Cold Blood as such a piece of writing, as did Elie Weisel in his novel, Night.

Typically, though not always, a short story follows one basic plot-line, which is its exposition, rising action, climax, and resolution.  Short stories tend to focus on one main conflict and the storyline progresses in order to resolve it.  Novels, on the other hand, can present several conflicts at once.  As a result, several plot-lines can progress simultaneously.  Anti-climaxes are also more prevalent in novels than short stories.

Because of the general difference in length of a short story to a novel, short stories often lack the character development that is both possible and utilized in a novel.  Short stories often have fewer characters as well.

In my opinion, short stories tend to utilize irony as a key piece of an entire story more effectively than novels.  It would be difficult to base a lengthy and complicated plot on one key element of irony.  Short stories, on the other hand, do this all the time.  It seems that because of their shorter length, irony (and ironic humor) is more focused and often plays a more significant role than it does in novels.  To paint an analogy, I think of skits (or sketches) as compared to full length dramas or films.  Successful skits (think of "Saturday Night Live") tend to be based on one or two elements of ironic humor.  When such skits are "extended" into full length movies (think of any "Saturday Night Live" skit that has been turned into a film) the humor often becomes ridiculous and over-the-top, and just as often, the storyline suffers as a result.