Moonwalk requires you to finish ladders in a specific order.
The challenge is extremely hard: it requires you to finish 10 consequtive ladders in ascending or descending order of positions, i.e. finish top-10, top-9, top-8 and all the way to top-1 or all the way around.
Another pair of patterns that may be used is top-5 to top-1 and then top-1 to top-5 or all the way around.
Winning chances are very high because this would be pretty much a normal Frontrunner run, except you would need to snipe positions on 10 of the round's ladders.