Not sure if you saw my clarification post, but the challenge in question was a FreeCell challenge which has 20 games, not 30. I agree with you that a 30 game challenge under 30 minutes would be incredibly unlikely. I don't believe that the timer starts until the first card is moved, at least in FreeCell. Not sure if that is true of all the games.
I did have one challenge where I finished second and PaltryAmoeba was first. His/her time was about 30+ minutes faster than mine.
In the challenge yesterday, I came in first in my group for a 30 game event in a time of 1:49:30. I was assuming that I would not be in the top 10 because because the games were quite hard for me. The Expert Tripeaks was very difficult. This morning when I saw the final scores for my group, there were only 5 people of the 100 who solved all the games. So even with the various challenges, there are some that are easier and some that are harder. So what were the top times overall for that challenge? The first place time for the top 100 was a 25:58