Embarrassed to say that I couldn't figure out how to clear the third level. The color-changing mechanic is a very clever way of playing with collision, and vaguely (vaguely!) takes me back to the days of Fireboy and Watergirl. The little bounce sound is a nice touch too. Love the premise, and I hope to clear the third level soon so I can experience all 10 levels.
I think the level you're talking about is the one where you have to wall jump for the first time. (Even if its not I'll still put this here as I've seen people struggle most with the wall jumping).
But when it comes to wall jumping, think about "real life" physics. If I were to go for a wall jump, but I'm jumping at the wall from 20 feet away, I'm going to lose a lot of momentum from gravity and the distance so I won't be able to get a good kick off from the wall, thus my wall jump will be weak and suck. However if I was to do a wall jump and I jumped at the wall from 2 feet away, I'm much closer so I don't lose any momentum and can get a much better kick off the wall, thus my wall jump will get me much more height and distance.