Animation is not used anywhere in the game. I try to stick to regular rigidbodies and joints. In some cases rigidbody setup is changed at runtime (e.g. catapult being the most complex gadget so far, re-rigs itself depending on player intention). Most of things that are scripted are reactive - meaning that I read collisions, rigidbody positions/rotations to decide forces (catapult, doors, bending bars, glass shatter, etc). With my background C# is the easiest animation authoring tool :)