Fighting games and beat 'em ups
Fighting games include a lot of fighting (surprise, huh?). You will be controlling a character (usually, badass looking) and will have to defeat another character that can be controlled by your friend or AI. Fighting games focus on close combat, so there will be a lot of blocking, attacking and counterattacking, combos or special attacks you can master in time (preferably, a short time).
Fighting games usually feature a variety of characters you can select. Each of them having different fighting styles or special moves. Character selection gives fighting games a good replayability, since different character usually results in different strategies you can use.
The main difference between Fighting games and Beat ‘em Ups is in the number of enemies you’ll have to face.
Beat ‘em Ups or Brawlers will do anything to make the odds very much not in your favor. You get to control a character and hordes of enemies will appear with a single goal - give you a hard time staying alive. So if you like to feel like a hero when tons of enemies are coming to get you - a Beat ‘em Up is just for you. Beat ‘em Ups usually feature a 2D gameplay and scrolling levels, but some newer versions offer a 3D experience with even more enemies to beat.