I’ve noticed that in the Level Up mode for Chord Crush, if you let the timer run out, it gives you a passing grade as long as you don’t have the requisite number of misses, even if you haven’t completed the requisite number of puzzles.
In other words, if you only get 3 puzzles correct and you haven’t guessed incorrectly when you run out of time, you’ll be recorded as having “completed” the level.