Bug prevents winning the game
When you start the game you are supposed to jump onto the jetty and you get rewarded your first 5 points. If you repeatedly walk west instead of jumping, the master thief will at some point grab you and throw you onto the jetty and you do not get the 5 points.
If this happens and you finish the game, you will return to the boat with 495 points instead of the expected 500. When you get into the boat with all the treasure, nothing will happen. You will then first need to jump onto the jetty again to get the missing 5 points and then reenter the boat for the game to finish.