The reason Jungle Climber does so well isn't just that platforming with your hands is implemented well - it's far more to do with the excellent way Paon applies the upside down approach creatively to the game's levels. Early examples include a big stone ball made of pegs, whose momentum you have to build and sustain by swinging alongside it grabbing pegs on the falling edge.
Not content with that, Paon throws loads at the DS' two screens, and far more of it sticks than not. A level where DK finds himself mirrored on top and bottom screens in a crystal palace challenges you to keep an eye out for differences between peg layouts in the otherwise identical scenes above and below the fold. If DK grabs hold of a peg that exists on one screen but not the other, the mirror cracks and he has to start again.