In this particular GTA you start out in a '92-'93 urban Los Santos (Pretty much LA). You are CJ a gangbanger who left the Los Santos area several years back to pursue other endeavors. But now something terrible has happened and it is time for you to return home. If you have ever seen the film Boyz In The Hood, the dialogue in the game are similar in many ways. Overall I think it does a good job of sucking you into the story.
For those who familiar with the GTA series, the control scheme and mechanics of everything are very similar to previous games. They have added a sprint function (tap the X button repeatedly) as well as skill bars in various things (guns, driving, riding a bike motorcycle, flying a plane, etc.) that you can improve in by doing that very action. Wanna level up your 9MM handgun skills? Take out your gun and start blazing, in no time it will level up and you'll become a professional. They have also added some features from Rockstar's other titles, like stealth kills which all you to sneak up on someone and kill them in one shot.
Graphically it's about the same, but the drawing distance is much further and popups do not occur that much anymore if at all. The coloring of the game is darker and changing the brightness does not seem to change it much. Load times have also been smoothed out to the point where they are almost nonexistent in game unless you enter a building.