I have a suggestion about the game window navigation. I noticed that the "close" button was not always at the same place, which is a bit disapoiting for begginners.
That's a detail, but the more important is that we would like to close the last opened window just pressing the "escape" key (as in many other games). This key currently opens the main menu which is not very interesting and always accessible from the top right button.
Did other players experienced the same feeling?