The route has two variations, according to Boston Rocks guide. One ascends diagonally and one goes straight up vertically.
About half way up the wall, you cross a giant horizontal crack which makes a pleasant resting spot. Other than that, there are plenty of holds for feet and hands, but they tend to be small and a little slippery, due to the nature of the puddingstone at Hammond.
If you stand facing Lower Wall, there's one giant vertical crack down the middle (it's called Free and Easy). To the right of this crack, there's a protruding feature which runs diagonally up, and to the right. This feature starts at the ground and runs up towards the top of Cracker Jack, to the right.
Hidden Magic follows this diagonal feature.
A variation has you starting midway between the start and end of this diagonal feature, and climbing straight up, rather than following the diagonal.
There are two trees at the top which can be used for anchors. They are about 15 feet back.