I have released an update to my animation/tweening engine: LeanTween. Updates include further optimised performance. It can be greater than 5x faster than the competing tweening engine iTween! I have a writeup comparing the speed of the two engines on my website. Also included in this update is the ability to have a custom tween function, created by passing an AnimationCurve to the engine. Download LeanTween for free from the Asset Store.