You're NOT expected to get 50 million points in a single scale run. My highest single scale run is a 7.2 million Major scale run, which was damn near flawless as I could get it. There are 11 scales to play. Each scale pattern can be played and will have it's own dedicated high score. Between these 11 scales, you're gonna have to pool your high scores together to attain this 50 million mark.
I have several pointers for those who are having trouble with this beast. First off, the first several notes will be a full scale run for whichever scale you want to play. In the "Select A Scale" menu, you will find a scale pattern on the bottom left corner of your screen. That is what you're gonna start off playing. It will ascend from the bottom (thick) strings all the way to the top (thin) strings and will descend from top to bottom. i.e., if you choose to play the A Major scale, it was ALWAYS start with the following scale:
A b c# D E f# g# A b A g# f# E D c# b A
I only mention this so that you can quickly blow through these first several notes to help get your speed bonus going. After the descend is over, it's all random.
Well, I take that back...when you hit a note, the next note will only be a neighboring note. In the A Major example, the A will always lead up to a b or g#, the b leading to a c# or A, and so on and so forth. Keep this in mind so that you can limit your options when running a scale.
When you select your scale, you will have your options of keys to play in. Since playing in different keys won't add to your score pool, I recommend sticking to the A major scale. Not all guitars are created equal and some guitars have terrible intonation. Guitarists will tell you the higher up the neck, the worst the intonation can get. This is especially true with the thick strings at high fret levels. The 5-8 fret range will allow for a viable medium of intonation and fret spacing. Since the game depends on the tone/tuning to register what you're playing, it's kinda important to keep that in mind. If your guitar has bad intonation that the 5-8 fret range throws the game off, you can switch the key to F#/Gb...or get another guitar. If you have a guitar with incredible intonation and want smaller frets to play with, go higher but ONLY if the guitar has good intonation.
When the scales start coming down at a quick pace, I don't really pay attention to what note I need to play next, as I'm more focused on the scale pattern itself. My eyes are focused at the END of the tunnel, instead of what's being brought to the front of the screen. I reason this because this is all just a game of patterns. If I can anticipate what's coming in the back end, then I can prepare of it. I don't know if that makes any sense, but if gets too crazy when the speed is getting too much, put your focus in the area of the screen where the numbers start to appear. It worked wonders for me, except for the Minor Pentatonic pattern. It's difficult as sin to read the bottom 4 strings at a fast pace.
Hope this helps. Any questions? Ask away. I'll see if I can help!