Trine 4: The Nightmare Princes developers hopes to return to form after what is seen as a general misstep in the previous title, Trine 3. Now some on the team have put out some new details about various aspects of the game, and how they hope to achieve that with talking about everything from the games length to its difficulty settings.
Source: N4G PC Trine 4: The Nightmare Prince Gets Details About Game Length, Difficulty And Much More