Immersion: primarily through combat, though graphics play a role as well, providing the reward mechanism. Its a lost opportunity, but at least in the lite version, users cannot rename ships, which would add some player agency.
Difficulty: in the lite version, this is adjusted through adding or subtracting the possibility of mechanical flaws, and weather effects.Other ways are not known. The interface thankfully does not contribute substantially, though not all of the buttons are obvious in their purpose, so players should experiment.
Lasting Appeal: Depends on the players success. A player who finds success in early levels and is rewarded regularly will like the game.
Personal Note: The game faces a challenge, how to address naval gunnery. I like the way this game uses an understandable angle of gun barrel over gun power, or some other, more arbitrary mechanism. How it is implemented is awkward, I feel this game could use an in game encyclopedia for things like ship traits and projectile flight.