Thanks for your feedback! I wanted to make it aesthetically pleasing so it is fun to receive and opening this "strange letter" might put you in the mindset of a cartographer from the past.
I have envisioned the game to be played in a chain, but from feedback I see there is a good amount of people who would prefer to send it back and forth. I want to avoid always having to deal with the same number, so I am currently looking into changing the procedure of generating the number, so each time it will be random, even if it comes from the same person.
...and I agree with the "one map" critique. As mentioned in other comments, I didn't know of Mapemounde until the deadline, and decided to join last minute and ask if it was ok with the organizer. I am glad I did - because the feedback has been priceless! Thanks once again.
Oh, and yes - I will work on the game more after the judging is done.