I am also rather curious about why not many finish the puzzles but the times are often either really short (even for hard puzzles) or rather long.
What I am more curious about is the fact that some of the puzzles are finished, if you look at the record time, in 10 seconds or less. Some of them, I can understand because some of them are not super difficult. I did, however see a cryptogram that had probably around 15-20 words and it was a difficult one. That one was solved in 5 seconds I think. I just want to know how.... I don't even think I could type in the letters for all of the words in that amount of time even if I already knew the answer.