At first, I was amazed. And then slightly jealous (I want a piano-playing cat too!) and then, the thought occurred to me....
There's definitely the spirit of a frustrated pianist stuck in the body of that cat.
I'm fairly certain the "cat" is banging away on the piano and is getting increasingly frustrated with both the failure of her communication with us and the fact that her paws get in the way of her previous stunning technique.
In one of the videos of Nora, her owner talks about her "diva-like" tendencies and how she doesn't like to mingle with the other cats.
Of course she doesn't! In her mind, she's thinking, "I'm not a cat like all of you! I'm a human! I'm better than all of you so don't try to get friendly with me!"