Oh, I remember that. It'll be interesting to see how it's implemented for this game.
Live2D from last year :
We had a thread about it last year
here.
For those in awe, for perspective's sake I'd like to point out that the gif of how her face is just layers positioned in front of each other is how folks animate in photoshop and flash. Every moving part is generally on its own layer. In Flash you can use "symbols" to make them into an object with many stored variations (like a happy mouth or sad mouth, etc) so that at will you can select and reuse different frames of animations stored for each symbol. In Photoshop you just setup your layer order and draw which is how Skullgirls did its art seperating linework, color flats, shaders and such into seperate layers.
Live 2d is essentially saying "hey since its hard baking animations and eats up memory, why dont we just make the model's body in 3d since its poses aren't ever going to get too extreme and use 2d animation layers for the face?" This way it can do a lot of stuff fluidly like a 2d animated face with squash, stretch and low runtime memory cost. It may increase loadtimes between things since it has more images to load but its a good runtime solution. Plus since the hard part to animate is all the foreshortening of the body and its poses keeping it 3d while leaving the face 2d gives some types of storyboards the best of both worlds with easy posing and body animation while maintaining simple and reusable stuff on the faces without having to fiddle with a ton of issues on the shader maps, specular maps, diffuse maps and what have you that typically have noticeable tricky lighting issues at runtime on faces.
Remember this if you were "wow-ed" by the cleverness of that layered face gif up there if you ever felt like griping about 2d animation in flash or photoshop being dumb.
