But why does it work like that? I know it picked up word fragments, but still, why does it work like that?
It detects letters in those phrases that are very similar to the original word. It's like that in case you spell the actual phrase partially wrong.
Also, the Brain Age 2 TAS is very similar to what this guy did, just with pictures instead of words. Props to this runner.
Any explanations as to how the Brain Age one works?
The game detects the drawings as the numbers/letters. It's a lot harder to do because of how precise you need to make the drawing to trick the game into thinking it's a certain character. Usually the image will contain a similar figure to the character, thus the game will recognize it as one. The way he does the piano section just depends on if he hits the note given on the screen at the time the arrow moves onto it. If I remember correctly, it's based off of whether you hit it or not, and not accuracy, meaning he can just spam the piano keys on the empty segments. The reason the keys don't appear highlighted when he taps them is because of how fast it is being inputted I think.