Martin Jonasson and Petri Purho on Making Your Game Juicy
A "juicy" game feels alive and responds to everything the user does.
This talk - given by Martin Jonasson and Petri Purho at Nordic Game Indie Night - demonstrates how juiciness can be manipulated.
Robert Penner's Easing Equations
Gamasutra: How to Prototype a Game in Under 7 Days by Kyle Gray, Kyle Gabler, Shalin Shodhan, and Matt Kucic
Emily Short - Make it Juicy!
The Disney 12 Principles of Animation
The Art of Diablo 3 with Christian Lichtner
Easing Function Generator
Thanks to Dr. Christy Dena for the link.