I completed the game, it was very fun.
I was not certain before starting so I was happy it was a full length game with at least a bit of everything.
Finding the third key was satisfying after visiting the castle first and searching there for a time. The last hint got me at first, dark river and stones made me think of the mine in the fishing town, but then there were not that many other places to try so I found the place eventually.
Action Points are the right addition to an Ultima-inspired game, and the exploration part probably hits the right spot for people who want to have to pay attention to what people say without having to take pages of notes.
Good job.