I saw sometimes slow-downs during the game, more often than previously, and it was a bit strange (in the casino on a close up it slow down, and then a wide angle there is no problem ^^ but I don't trust windows, so...)
Lightining, animation, even the backgrounds are very, very improved in this episode ! it was just 2 hours of game for me, very short, but I loved it more than the two others... music is so beautiful, you even cut the street intro ! I also find this episode more exciting.
And I also love the yo ma's thing... reminds me monkey island
I don't even think how episode 6 would be

(I hope also it will be longer of course... ^^)