From top left, clockwise: Futuristic Dream by Supershroom (2nd place, 15.17/20), Mushroom City by Coinshower (4th place with a cookie, 8.56/20), Primetal City by 1018peter (3rd place, 14.94/20). Winner (centre): KoopaCorp™ by KABOOM (15.65/20).
This LDC was the by far least successful one in history and forever will be (because I don't know what will happen if we should ever finish an LDC with only three entrants after a 3-month deadline). It wasn't even the fault of the theme, it was just a big hole where almost noone was motivated to enter. Right before the end, Coinshower jumped in, and he was rewarded with a cookie for that. Judging took also quite long for only 4 entrants, with the panel not even being complete when the final deadline was reached.
KABOOM took home his first gold with a score of 15.65, two hundredths lower than MP3's Hell's Rebellion, which was the lowest winner before. He was also the one who took the longest time between joining (October 2009) and winning. Shroom and Peter both received their first trophies. The uncommon line-up with three bronze-tier designers was displayed by Nan in his quite hilarious forum story Three Little Designers (scroll down a little)