Playing the Broken Grand Piano can sound a little bit funny as it is not tuned, so it is bound to drop Cranky Crotchet Level 1 which can be merged up to Abominable Melody Level 8.
At some point, the Broken Grand Piano will drop a Metronome, which needs to be fed into the same piano to improve the sound of those cranky notes! Then, the piano will turn into “Playing the Broken Piano” Level 1 which has a built-in metronome. In order to get Clean Crotchets instead of cranky ones, tap on the piano on beat with the Metronome. For example, when the Metronome is pointing to the left, tap on it, wait for it to get to that spot again, and tap on it as many times on the beat as you can to produce pure notes.