Game is looking good so far! I like the reasonably challenging nature of the levels and the boss.
Unfortunately the boss was rather vulnerable to just "run in, do one sweeping attack, run away, wait, repeat": no matter which attacks the boss does they don't need anything except that one pattern. It's possible to jump over the boss's low attack, so maybe it'd be nice if (maybe 2/3 of the way through the boss's health) she starts doing a low attack too quickly to run away from so you have to jump over it instead? Something like that to mix it up a bit.
At the moment the interaction with characters in the town epilogue is somewhat painful as I can't find any way to progress through their text: LMB causes the character to just attack, which is always embarrassing in peaceful village zones, and pressing "up" a second time doesn't advance either. I just need to wait, which is rather boring.
Apart from that, though, this is looking very promising. I particularly like 1) the animations - very fluid and satisfying, somewhat reminiscent of the original 90s rotoscoped Prince of Persia; and 2) the hidden areas - though as another commenter said, they do want some more reason for existing than they have at the moment, obviously.
Good stuff!