Hii
Right now I'm seeing this from my phone (sadly, I don't have the game here but in my laptop, and that thing is charging right now), but I think I remember some data that will help you.
I tried to play every final of the game when I got it, and that unlocked me the "???" section, and I think the achievement "In love with love" also gets unlocked when you play that section. (I'm not really sure of the Last part, so when I play again, I'll post the correct answer here)
Hope this helps! <3