It doesn't need to be updated, it's a reflection of the older days.
Anyways, look at the back of the box. 1-2 players.
You need to find an icon in the game with two hands holding, and press start on Controller 2. With help finally at IGN, I got a picture of where one of the icons is at:
It worked. You can mess around in two player mode now, just that it doesn't allow the two chars to be in two different cars or be too far away. Both can be in the same car though, one drives and the other shoots. There's also a way to play pool with a friend but I haven't tried pool yet, as well as other two player things I can't think of at the moment.
I also have a way of being able to fly a plane before doing any missions.