my recording in Bach invention no.4, with phrasing hints. I wonder what people will say about my playing....is such a way of playing Bach acceptable ?

http://www.youtube.com/watch?v=uSncAufUdZ4

For the 1st version - personally I find you pull the tempo around a little too much for my liking - particularly because you seem to consistently hang on the first beat. If you used that more sparingly it would be fine.

For 2nd version - I sometimes practice like that, changing the rhythm around. I find it helps memorize the notes. Wouldn't perform it that way though...

I think you'll find John's comments pretty standard. Most pianists don't play with so much rubato in Bach. Many harpsichordists, however, play with that kind of rubato quite often, and it's definitely a valid approach to Bach interpretation. (You'll find it much more common in French harpsichord music, but it works for Bach as well.)

As for the phrasing hints, they're good, but I'd urge everyone to look at the big picture - where are the phrases that are 2 and 4 measures long? How do we pace the dynamics over the entire length of the piece?

Why did you pull your performance of #1 off of YouTube?

I try to play the piece using idea of harpsichord. As I haven't learn harpsichord before, I don't know if my interpretation goes wrong or not. Kreisler, thank you for your comment.

My performce of invention #1
http://www.youtube.com/watch?v=dUEzCy2o7PE