FNF HEARTBREAK Vs Girlfriend is quite the special mod in Friday Night Funkin', and the obvious reason for it is that the game will now feature a fight between Boyfriend and Girlfriend, a musical one, of course, even better since it takes place across many amazing songs, such as:
Boyfriend Vs Girlfriend, an FNF Heartbreak mod!
Make your choice between the story mode and free play mode in the game's main menu, and then, in either case, give your best to reach the end of the songs by hitting your notes according to the charts, which is how you get there and win the battle.
So, when the arrow symbols are matching above BF's head, that is when you need to press the identical arrow keys. Miss doing it too many times in a row and you lose the whole game, so be careful not to let it happen. Good luck towards winning!