Really.
Ok, that wasn't technically an Xbox game (I chose that example because it was so similar to the proof of concept), but you can consider instead
the augmented reality part of Kinect Party, which is technically the same thing.
In that specific case, the only detail in the video was the "grabbing" gesture, which wasn't supported by kinect1. But that's nitpicking (there are other ways to select an item in a menu through gesture), and it is supported by kinect2 anyway (and the first demos were done with kinect1), so it's hardly "science fiction".