make jumping "stairs" to the left side and go up...you'll eventually find a point where you can jump through the windmill things. build a straight platform just higher than the center of the lower left windmill. move left and drop down in the open area (after you make a platform to land on) from there you can make the jumping stairs to the left with proper timing.
Hope that helps, although it probably made it more confusing
I've finished the game in around 70 minutes.. does anyone know how to make the time better? I tried finishing a level faster than I did, but the recorded time stays the same