So far really enjoying this. A PDF, yet there is more content than the original Heroine Dusk. 

• A stateless game (rather, a game with ~200,000 discreet states) very clever.
• Gating player progress to keep the number of discreet states less than infinite. Very clever.
• (Most of) the puzzles are very clever. The clues are not obvious, but also not so obscure that I can't figure them out. I am enjoying them quite a bit.
• (exceptions to the above) The shortcut over the soup thing I find incredibly irritating. Having the player scroll to an otherwise unlreated page as a solution to 'climbing' up a wall would be clever, except that the game so far has established that scrolling to other pages outside of the internal hotlinks is outside the scope of the game. For instance, the 'unwinding time' mechanic uses the previous-page hotkey. Very clever, but you had established that within the context of the game. This solution never occured to me because it felt like cheating. I kept trying to click the top of the wall looking for a hotlink that would take me to the appropriate page for climbing over it. If the clue had said "use your mouse scroll wheel to climb the wall and find a shortcut above the blah blah blah..." that would have established that scrolling to an adjacent page is within the game's intended mechanics.
• The portal activation/Druidic numbers puzzle was not quite so egregious, but adding some clue like "press Ctrl+G to chant an incantation" would have helped establish that jumping to a specific page number is not cheating.
• The book based puzzle for opening the portcullis to exit the mausoleum is beyond my ability to solve. Either the clues within the folk song are far too vague, or there are some ambiguous interpretations of the underlying meanings of the Futhark runes. Again, this strikes me as expecting players to break immersion to solve an in-game puzzle. Did I miss a book/clue linking the folk song to the rune's meanings within the game? or are players expected to 1) know what futhark runes look like, and 2) know they each have underlying meaning beyond their phonetic componenets? Either way, the hidden clues within the song correspond to more than one rune in such a way that the total number of valid combinations is still over 64, or they correspond to the wrong runes entirely. What am I missing?
• At first nearly all of the music hotlinks go to urls that simply say "Page unavailable", but that doesn't seem to be the case any more. Loving the music. Excellent ambience.

• shortcut over the fire: That is a fantastic solution. Anyone (like me) who isn't quite getting it and clicking the top of the wall (which means they understand the puzzle in principle, at least) will see that extra clue to guide them.
• portal incantation: Haha! wonderful. I like that as well. Again, this one didn't bother me so much, but that is a good way to flesh it out in my opinion. I must admin I'm taking notes from you on how to craft clever puzzles. 
• folk song: Like, literal compass directions traveled by the knight? From the plains, north to the temple, back south through the plains, south (or possibly southeast?) through the town, south to the knights college, (so ... south twice?) Then over the river east? If that is even remotely related to the solution, the issue is I am unable to go back and retrace the knights journey outlined in the song because I am trapped in the mausoleum. The only other "directions" in the song that I could find was "up", so I assumed the solution was based on Futhark esoterica:

• "... as wisdom was his goal..." (Ansuz rune: understanding and wisdom)

• "...to become the bravest..." (Uruz rune: courgage and strength)

• "...of the newborn realm..." (Berkano rune: birth and sanctuary)

• So I was way off, then, huh?

P.S. I did also enjoy the nod to day the earth stood still and/or army of darkness on the portal incantation puzzle. An excellent red herring (or alternative solution, I guess)

Wait... Either I have entirely missed a clue that connects those locations to this puzzle, or all the locations in the song do not correspond to their in-game locations. According to the game's map, it would start in zuruth plains, go north to the temple (quite far north, actually... or north-northwest), then south (or south-southeast) to the college, then (after a short jaunt back north a bit) east across the river:

Also, there seems to be multiple names for these places:

• Gar'ashi Monastery vs Monks Temple
• Templar Academy vs Knights College
• Canal vs River

That, or none of the places referenced in the song are experienced by the player up to that point. Which, if that is the case, how is the player supposed to know where those locations are in relation to one another?

Regardless, I think including the specific compass directions in the song is an adequate solution. If it were me, and there was room for one more bookshelf in the mausoleum, I would leave the explicit compass directions out of the song, but add an atlas somewhere that shows the general location of the places mentioned in the song, so the player can put together their relative directions themselves:

Though, maybe there isn't enough pixel-real-estate for a map like that. 

I'm a bit in a hurry right now, but I'll get back to this later this week.

Take your time; I've got plenty of pages left to explore. :)

I got the directions messed up due to how my development tools having the map reversed...

That certainly explains things. It makes me feel better about not being able to figure out that puzzle. Hahah!

Your "extra book with a map" idea is excellent, but not sure I'll go with that due to my limited graphical skills...

Well, I'll try my hand at making somthing like that for you. If you don't end up using it, I will still have had fun making it. :)

Here's what I've got:

It should be fairly easy to edit, too. Let me know if you'd need something adjusted in order to use it. (License: CC0)

Source file: undying-map.xcf

Yes! good. I am glad you've decided to have a map book, even if it isn't my version. I'm going to start over with this new version (I like new beginnings). Thanks for making this game.