The ship is a psychological game in which your primary objective is to kill one person, while ensuring your own survival. There is someone out there to get you too, but you never know who.

You find yourself on a 1920's era cruise ship in the middle of the ocean, so you can't exactly just get off. You're given instructions to kill one person, and that's it. You now have to find that person, get a weapon, and make sure you get away with what you have to do. There are weapons everywhere, some obvious, others not so much. While you are hunting your prey you are suddenly reminded that you are human, and as such you need to take care of yourself, just like everyone else on that cruise ship.

You start to get close to your prey, but you must be careful not to give yourself away. You also need to watch your back, who knows which of these strange people are out to get you too. Make sure you travel safely, never with a weapon too out of reach.

So you killed them, good for you. There's some time left, make sure you don't run afoul of someone you really wont like at the end of the day. But that one's over now. Do it again.