Seriously debating on uploading this to r/oddlystaisfying
I truly understand your feelings on this.
You should. It’s much more satisfying than watching a 1000*C knife cutting through some poor material.
Although it may be your intention to leave it in there for alignment, you could remove some of those 'cout’s and semi-colons e.g
// Introduction
constexpr int WORD_LENGTH = 7;
cout << "Welcome to BULLS & COWS!\n"
<< endl
<< "A game where you guess the "
<< WORD_LENGTH
<< " letter isogram I'm thinking of.\n"
<< endl;
Not sure if this is more oddly satisfying to you or not 
Something to keep in mind. Thank you.