i already know a lots of tricks like zipper matrix skin the gerbil mach 5 boing bong ninja vanishes few GTs budha revenges 1.5 slack mounts all mounts whips even ann connolys magic trick AND i still cannot get through barrel rolls… that trick is just impossible to do for me ;< i knwo the motion all steps but when i am doing it fast i dont get this effect :< 5min ago i watched just some random yoyo video with some kid 
and what i noticed at 1:14 that he has the same problem as i do 
check this out i ahve the same problem with lack of that second rolling motion :< how to fix it
Now I"m wondering if I’m doing my own right. 
A video of “this is what I want to do, check 1:15” and “this is how I actually do it” (the kid’s video or one of your own) would be helpful in identifying the problem and giving you pointers on what to fix.
I think mine look more or less like that, too… except that when I do the underpass, I’m actually launching the yoyo a bit and going faster. Maybe that’s the only difference? Momentum and smoothness of the non-throw hand?
They also look better with less string. Not sure how you can have shorter string until you’ve already done a few, though, and by then you’re about ready to go to the next part of the combo.
Now for the video where they look perfect to you!
For that second throw, try to shoot the yoyo forward and up a bit, and launch it into that string pretty hard.
Hope this helps!