Indiegames notice that Crayon Physics Deluxe developer Petri Purho and Martin Jonasson, creator of Jesus vs Dinosaurs, talked about tweening and juiciness at the Nordic Game Indie Night 2012. What's your favourite sort of juice? Orange or mango maybe? Or more likely it's jaunty music, uncannily large eyes that blink on impact with projectiles, and a little bit of delay and wobble. Confused? All is explained in the fifteen minute video. Purho and Jonasson have built a simple Breakout clone to which they can add layers of 'juice' and you can play with the program yourself.
There's an important lesson about design lurking among the silliness and I can think of a bucketful of indie games, particularly from jams, that would benefit from the addition of this sort of thing. Maximum output for minimum input isn't precisely what juiciness describes but it's part of the technique. It's the interactions in World of Goo that I'm always reminded of when I hear the word in a gaming context, the sounds and the squishiness of the hapless little balls.
The mention of Emily Short's claim that this sort of thing can happen in a textual setting is particularly interesting, reminding me of the not-entirely-textual Time Gentlemen, Please and the many wordy rewards it contained for the explorer of inventive interactions.
I'd be interested in seeing other demos, like the Breakout one, exploring different types of game. I maintain that the high point of juiciness in the FPS genre is Rise of the Triad's 'ludicrous gibs'. Or anything involving flare guns, dynamite and Blood.