I havent played GTA 5
But GTA 4 is abt Niko Bellic from Russia comin to live with his cousin Roman Bellic in America and the rest as far i played is about getting a decent life.
They use realistic Physics like if u drink, you cannot walk straight and vision becomes blurry, you can shoot out of the windshield if you are going at high speed and crash. The map of LC is entirely different from GTA ADVANCE AND GTA 3
You can go on activities with people and there are some random ppl all across the map who can give you a mission
Its not bad, you can try it out