This is really nice, the soundtrack is lovely too!
I’m stuck on chapter 4, would love a hint if someone has one 😅 Here’s my (incorrect?) understanding of the rule, in ROT13:
Bar bs gur cynargf vf n “yvne” naq jnagf bar zber be yrff guna vgf pbybhe jbhyq hfhnyyl fhttrfg - V qba’g xabj ubj gb gryy juvpu cynarg vf gur yvne gubhtu?