Hi ! This cheevo is finally obtainable since 03/03/16.
I wish you good luck cause World 5 is really insane.Especially levels 5-11 and 5-14.
Here's a video to show you the 15 levels on 3 stars.Thanks to Robotosis for the awesome vid ! (PC gameplay):
Hopefully you don't have to get the 3 stars in one run.It's possible (and recommended on hardest levels) to do separate playthroughs for time and accuracy stars.
Once my Upload vids are available i will show you my run of the level 5-11,cause the timer is insane and the gameplay on the PC version is nearly impossible to do on X1.
Good luck guys !
And if you have a problem,don't hesitate,i'm here to help you.Feel free to ask me all your questions ^^