A meteoroid is heading towards Earth; can you manage to escape the destruction? Well how about visiting strange new planets and fighting space pirates?
If you make the right choices, you will continue ahead, but if you make the wrong choices, it will be GAMEOVER. Yes, this is also known as a Game Book. So you get to decide what happens next, and also how the story ends.
Remember, there are multiple endings that you can achieve. Some are good, some are bad and some are neutral.