Let's say your character starts the game rudely awoken from hypersleep. Maybe there’s a power failure. Maybe a meteor strike has caused a hull breach, or the Alien itself has sabotaged the ship’s systems. Whatever the problem, maintaining a failing living environment should be a major element of the game. In fact improvisationally fending off death, whether it come by Alien or environment, should be the game’s only ultimate
objective. Just like in the film.
The ship should be a dark, dangerous, self-contained open-world with a limited lifespan, extendable only through the decisions and actions of the player. Do you move out to make repairs, risking exposure? Do you reroute power from a less vital system and hope that it doesn't become very vital further on? Do you even venture out at all, or just try to hunker down and hope you don't get trapped by the Alien? This should be a Xeno survival and ship management simulator, and much like in a 'sim' game like Dishonored, there should be no right or wrong approaches. Just on-the-fly appraisals of developing situations, risk-and-reward resource management and hope.