Metalcore is a name given off to several new heavy metal bands that not all of them deserve. I consider metalcore to be shit as in most headbangers ball bands besides Shadows Fall and Lamb of God. Killswitch engage IS true metalcore, but they are the only ones that do it right and are cool at it. Alive or just breathing has some great songs and cool guitar riffs and the last one was ok... Shadows Fall evolved from a wannabe death metal band to a thrash influenced metal band while Lamb of God evolved from a wannabe hardcore band to a more complex testament inspired metal band. I also have heard someone describe metalcore as having lots of "metal breakdowns" which people complain about, but if this was true then Anthrax would be a metal core band cause they always had those mosh parts. And those mosh parts ruled. Especially the part in Indians after WAR DANCE!!!!! Im gonna crazy when I hear that live in illinois!