Oh this world is kinda tricky. I have beaten it again but it was very hard. I think you already know if you jump once on this plattform it changes direction. try to collect every single coin cause you will need as many lifes as you can. Try to avoid enemies cause if you jump on them it's hard to get back on the plattform.
It's very hard so you should also get as many lifes as possible from another world.
I hope you can bet it good luck
Edit: Lol I just found a shortcut. When you get to the plattform, right at the start, jump down to the hearts bottom left. Then you finsih the level immediatly.