These are pretty explanatory but let's go over it. Realism is to make the game look as realistic as possible to emulate real life. Personally I find this boring because they end up looking generic a lot of the time. Cartoon is where they make it look like animated shows or movies or anime. You don't have to settle with looking like it's real, it can look unique because of the artstyle or generic. I find this one more interesting because no two games in this style unless in the same series(possibly) look alike