This achievement will be awarded for scoring 10,000,000 on the guitarcade mini game Ninja Slide N.
This mini game requires you to slide up and down the strings to specific frets.
At the end of each game the stat screen will show 3 challenges that when complete will go towards levelling up you multiplier, You can only complete 3 challenges at a time and for every 5 your multiplier will raise one level.
Challenges will be anything from "Perform 20 perfect slides on the red string," "Reach 100 Towers" to "Slide on every colour string"
Now it's important to get your level up to around 7 or 8 to give yourself a high multiplier,
While your sliding if you can stop on the correct fret without stopping early or overshooting this will be classed as a perfect slide and for every 3-4 perfect slides you will get a massive amount of points and it will change one of the "Ghosts" to a colour change ghost.
Hitting these ghosts, perfect slides and changing strings are critical to getting the 10million.
Good luck and practice, practice, practice