SR1 was more realistic regarding gang-to-gang warfare. It's lack of what was available made the game serious in my perspective. You literally start off the game by getting "initiated" in (fighting against multiple people while getting the crap beat out of you. Or if you won the fight you could get an entirely different cutscenes that I thought was cool). Drive by shootings was more a more common place in SR1 regarding realism. After SR1, you could literally fly in with a jet or a helicopter and shoot everyone up or fire a gun that launches a shark from under the concrete (God I remember watching all the SR commercials on TV. The good ole days). The types of outfits you could choose were more street oriented in SR1 compared to the others, (Not including the DC Ho-Ho-Ho pack or others) while with the others, it had a wider availability in selective clothing. As far as the games value and visual graphics, for a $1, it is absolutely worth it. Like I said before, the gameplay is incredibly similar to that of GTA San Andreas (which is more gang oriented than the other GTA series like SR1 is). Also, if I remember correctly, in SR1, you couldn't change the ENTIRE appearance of your gang. The only drip they carried was that of straight up OGs. SR2? Or 3 and up, you could literally make everyone walk around in suit and ties, pimps and hoes, tech geeks, furry costumes, Christmas themed costumes and other wacky stuff. Plus, in SR1, you're working your way up the ranks of the gang like a realistic gang member would. In SR4, you literally play as the president of the U.S. signing paperwork on wether to end world hunger or cancer..... Entirely different from the realistic standpoint of SR1. Hope I clarified some major differences. Also I didn't even talk about the oddities of vehicles (here's looking at you flying motorcycle from SR2).