I didn't attempt the trick in level two by headbouncing and still collecting the apple. It's a lot of effort to do.
I found out you can collect the middle apple of 3 on level 5 by holding right, hitting the wall, and then switching directions (letting go of right and tapping left for just a moment) on your way down to hit the bounce pad. Then, you can come back up to get the one on the left and go towards the exit. The timing seems pretty tight but it's very consistent once you get a feel for it.
