3, 5 and 7. In short the steps, where you have to reverse your momentum. I get it's a skill thing and just about practice. The one time I got through all the steps to the next part I just panicked and jumped to a tile that wanished :) But from what i saw that part is mainly just about timing and not too much skill.
Now that i tried again for a while, more difficult part for me is "catching" the small segment of a wall between spikes while falling from a higher place. As in while my falling momentum is greater. But with practice I'm getting better.
Key for steps 5 and 7 is to press and hold opposite movement direction just a fraction of a moment after jumping from wall.