When the Trine 2
developers Frozenbyte set out to make a downloadable add-on for their co-op adventure, the end result became so substantial that the term 'DLC' doesn't accurately portray the new content. They've decided to instead call it an expansion pack. This new dev diary (it must be pretty big if it's getting its own dev diary) examines some of the concept art and design behind the add-on.
Look for the expansion soon, though no specific date has been announced.