It's difficult to analyse those indirect shadows with that footage alone, but it seems the characters don't cast them into themselves, SSAO does that though -but its hard to tell-
I couldn't spot a any part where there are such kind of shadow being cast from the environment into the characters, still they do have good ambient maps like Unchy3 had, and finally, from the small amount of dynamic geometry in the demo - the moving clothes in the closet, and the furniture on the desk where an enemy's head is smashed into - that didn't look like was casting those shadows either, aside from the SSAO again... Yet, there are instances where the same character casts shadows into different directions simultaneously.
I would bet they are done per character, like many UE games still do today, they are probably pretty low res as it is a little blocky as Graham pointed out. Then they blur the shit out of them, either in texture space or as they are projected into the scene, and they have some sort of distance attenuation, not unlike oldschool Max Payne 2 had. All of that is of course just my speculation, on how I think I would try to do that if wanted to achieve what was shown in the demo. If any of my guesses are true though, they must have some really cool offline tool to bake in the places and the directions these shadows appear with cohesive results.
