Allow me to preface this by saying that I am in no way a Batman 'buff.' My knowledge is rather limited, but I think this description still holds. I do realise, for example, that occasionally characters (such as the Joker) will eventually die in comic series. That doesn't prevent him returning in other media.
Being Batman would be a nightmare. Apart from the horrors of the brutal murder of his parents as a child, Batman lives bound by a set of principles that ensure his constant torment throughout his adult life. These rules exist both within him as a human character, and as unspoken but immutable laws of the Batman universe. Each night he must sally forth from his Batcave, to combat the endless criminals whose sole purpose is to destroy Gotham City, and by proxy, torment Batman. As a character, Batman is defined by his unquestionable need to safeguard Gotham. By contrast, his various nemeses are defined by their insatiable need to create mayhem, and thus, cause Batman pain.
When speaking of Batman this way, differentiating between his depiction in comic books, movies, television series or videogames is not even necessary. Whatever the medium, Batman lives in a kind of gameworld. The peculiar narrative content of the superhero thwarts the usual procedure from beginning to end, where conflict is resolved and heroic characters can live happily ever after. Batman's need to defeat his enemies stops just short of actually killing them, bound as he is in a deep sense of righteousness. Whether in comics, movies or videogames, Batman's overall goal is to lock such villains as the Joker in prison or Arkham Asylum, not put them in the morgue. So whatever else defines the contest, there is (almost) never any chance for permanent victory.