Really ? this is very odd. I never faced such a problem, I just tested it today on the "Gamejolt" website and I played it to the end with no problems. It maybe a problem with the browser version. I suggest you just download it and play it on your pc.
Oh wait , when you accidently try to use Naz's magic and it shows no spell you can press "ESC" button on your pc to go back. you are not soft locked.
If that doesn't work then you can try to play it on "Newgrounds", here is the link: https://www.newgrounds.com/portal/view/755243