Today's advent calendar window hides behind it one of Jon's favorite games of 2009. It's not the most well-known of the titles we've been playing this year but it's great fun nonetheless.

xxx is a puzzle game that will remind some of the highly-rated Portal. Instead of that games portal creating gun, you have a gravity gun that can attract or repel objects. It is an interesting puzzle game, and is absolutely fantastic quality for a free game - Jon