The object of the game is to reach the rating levels that you chose by getting an education, earning money, being happy, and the way in which you do this is totally up to you. You can choose to be a bludger, live in cheap apartments, and work at Monolith Burgers all your life, OR you could go out, get a good education, get the Top job at the factory (which is the highest paying in the game), buy some luxurious items, and live in a classy hotel/apartments. All in all this game is about living life, it's not quite as involved as The Sims, but none-theless it's a very addictive game, and can keep you occupied for hours.
