I think if you add a plane to escape with 3 bosses to fight who provide key components. You might can add a small single page story that determines an actual deadline and lock the cartographer. As e.g. You are engaged (180 days) or you have an important career meeting (90 days). That you can actually “fail” the game when choosing story mode.
Also I would like to see some clues at or during the game about the 3 bosses. I found out about them through the cartographer as it gives it away with those red skulls. What if 1 skeleton for each boss can be found on an adjacent Island of that boss. With a letter that decribes shortly it’s horror and purpose (plane part).