This gets wild. Time to cover some issues.
Did the treasure map ending and escaped that way. Managed to free the bard but couldn't do anything with him so no idea if there's another unexplored path with him. I can't give the makeshift comb lute to the bard or really do anything obvious with it.
If you want to make interaction points a little less frustrating you should make sure that every single interaction point (the nest, locked doors, etc) should give interaction dialogue by default.
Very often it seems like it's very easy to break dialogue order and trigger dialogue lines which you shouldn't be able to access in the current context If you get the sparrow without talking to the lady and only talk to her after that she still gives you the task and the sparrow is RIGHT THERE.
After returning the sparrow to the lady it goes away again and I can capture it one more time but this time I no longer have the option to return it to the lady. Not sure if a bug or just an endless cycle of negligence that's intended so that the sparrow can be used for another purpose.
Since the game allows you to inspect objects at any point and that counts as dialogue you can trigger the animation while Dirk is facing backwards.
Pressing the escape key triggered this screen at one point. This is after starting a new game 3 times in a single run. The ESC menu was stuck like this from that point on for the duration of that session.