Things that were difficult to animate

My current favorite game, Dark Souls 1, does some animation very well, and in other places takes shortcuts. For example, water and slime look very realistic. This shiny visual effect is called “specularity”. Characters’ hair, however, is tied back and immobile to keep things simple — flowing hair is very graphics-intensive. The flowing cloaks of the Baldur knights were animated using the physics engine Havok, and they don’t look quite right.  From what I understand, the Havok engine has made a lot of progress since DS1.