Thanks a lot for the detailed feedback first and foremost. I'll try addressing the issues you mentioned.
Art- I'm glad you like it. I was very insecure about its quality but it's good to hear positive feedback.
Story - I really wish I got insight into this early in development as I would've changed a lot of content. A little bit of context first. I made the game's world for a dnd game for my friends but it ended abruptly due to various reasons. I wanted to make the game as an outlet to my worldbuilding itch and I lost sight of what makes a narrative game unique. This is why I gave a lot of exposition about the world through the characters rather than telling it through their personality. A mistake that I shall fix in my new project.
The chapters being unlocked was for returning players as you guessed. The way to get money is to talk to Ben (the mage in the robe) and find a way to knock the goblin out. I should've structured the introduction better. An amateurish error. If you wish, I can write a walk-through for future players who might get stuck.
UI/UX - This was definitely a weak point as a lot of the points you mentioned have credibility. With regards to the portraits, I initially planned for them to be much more detailed but because of time constraints and other issues, it was not doable by myself. Still, this is a very good lesson to learn and I deeply appreciate your detailed critique. Have a great day!