The name Martin Scorsese is pretty much synonymous with gangster movies - since his 1973 movie Mean Streets, he has directed several of the greatest of the genre in cinema history. Goodfellas, adapted from the book Wiseguy by Nicholas Pileggi, is one which arguably compares to The Godfather when it comes to classic movies about organized crime. Scorsese is also no stranger to violence, and Goodfellas isn't without its fair share of bloodletting. Mobsters tend to whack one another fairly frequently and often over small matters, as happens when Tommy (Joe Pesci) and Jimmy (Robert de Niro) brutally beat made man Billy Batts to death over a petty insult. A truly vicious scene, it marked the arrival of Pesci as an on-screen psychopath like no other - it's a performance which fully warranted an Oscar. See Pesci completely losing it in Goodfellas for yourself. https://www.youtube.com/watch?v=J8OwyOah0Cg
