I wasn't going to share this until I did it in a run but I don't think I will continue running this game. In chapter 3 after you go to the up to see you need the key instead of going down the stairs again you go around the top until you reach a gap. If you jump correctly then you are able to go across that gap. It will save a few seconds.

Can you consistently do it? With the not-great jump mechanics, I hit it only about half the time.

i know of the 5 or so sec time save in chapter 2 right before the elevator if you look to the right before the crows they wont slow you down to a walking speed and wont lose time i did the skip in my WR run

The jump was pretty consistent when hit from a diagonal.