been really curious about this
#Is the 'Say Goodbye' crystal heart in Core B side referencing farewell?
tight viper
farewell was added in the 1.3 update, whilst core b has been in the game since launch, so it is highly unlikely that it is a reference
rugged sun
I assume it references the fact that you've beaten every level in the game (-c sides)
iron grail
maybe
ocean stirrup
It's a rickroll
tight viper
it doesn't need to reference anything 
there's 23 other heart in the game, 24 if you count the fake one in farewell
eternal nova
I'm fairly certain it's either a goodbye to the player since that's the last thing they would have done (before Farewell was released), but then again Farewell was planned somewhat before the game released, I think. So it's likely just a small foreshadowing
tight viper
I'm fairly certain it's either a goodbye to the player since that's the last thi...
c-sides are all forced to be played post 8b
eternal nova
c-sides are all forced to be played post 8b
Oh right, I forgot it was on the B-Sides, not C-Side. My bad.
scarlet garden
all the b-side hearts are named after the b-side songs. the 8b song is titled "The Core (Say Goodbye mix)"
frank cloak
i thought the songs were named after the hearts? cause ik maddy named the songs