Perfectly Formed

Waterstones are running there first ever short story competition. They're looking for a story that is "small but perfectly formed." (?!) Its open to writers from the UK and Ireland. Stories of 2,000 words or under. Looking at the short stories I've written to date I think competitions and submission guidelines have certainly had an influence in the length of my work, most are 2,000 words or under, the longest being 3,000. There is a skill to writing shorts but does it limit a writer in some way if you don't explore a longer short story form? I'd be interested to see how I'd get along with a longer story of 5,000 to 10,000. http://www.wbqonline.com/feature.do?featured=505