Rocket barrel ride section is extreme nightmare, especially for W4, thanks for unfair hitbox of barrel and volatile controls. Try to fit 3-4 tile-wide space with this. Lack of checkpoint prior to this section multiples frustration, if you try to beat this level w/o savestates.
Can you score 50+ points in Flappy Bird?
P.S. I always find any level designed with Wiiqwertyuiop`s rocket barrel sprite to be an absolute hell to beat, thanks for volatile controls and inconsistent hitbox, that oftentimes registers crash into ceiling without even touching it.