Re: Chopin Em Prelude above
I started working with my teacher this year, and the Chopin Em Prelude is the first piece we worked on. Since it's the first time I've ever had a teacher and I last played self-taught 35 years ago there's a lot to work on - I was stuck without a teacher for a couple years now. That said, this is how we approached it and what he emphasized:
- learning how to pedal properly (since this was my start), and understand timing of pedal for this piece
- LH softer than RH. Since I was learning
everything for the first time, the first step for me was to simply make the hands as ridiculously different as possible to get the coordination. For my degree of control, that wasn't that much different.

- timing,
to begin with, accurate and mechanical -
then I was ready to play with rubato and expressiveness in general
- the triplets were tricky, and I think I spent two weeks on two against three one. The triplets went in two stages: a) get the basic timing of triplets right, b) some stretch to them to make them expressive within the sense of the piece. If I had not gotten "a" right, then he would have had me leave the piece at that level, and make it fancier some other time in the future.
We've talked a lot about rubato. For rubato, you should know why you are doing it, and you have to be able to do rubato while not destroying the pulse. Very often I ended up with something ridiculous or cliche first, and I've spent a lot of time chasing a sense of pulse. I think that is why we begin by playing very evenly and precisely.
In your clip what I noticed was PEDAL. There are a number of places where the chords wash into each other where I think you would want to pedal more often. It is the most noticeable at the end where you have plenty of time to change pedal. Personally I thought it sounded rather nice.
I wanted to add my clip as another student but my face keeps popping in and I'm shy

There's someone who thinks he can fix that, so maybe I can upload it later. (Is upload the right word?) There's a lovely single wrong chord in there but well, it was mid-practice.
------------------
Addendum: We looked at a number of performances of the Em Prelude. No professional pianist seems to play the LH totally even, "as written". I rather like Tiempo's version, and there is sense behind every single thing he does. I would not imitate him because I have neither the technical ability nor the understanding.