While linear formats like novels, plays, and stories are becoming more multiform and participatory, the new electronic environments have been developing narrative formats of their own. The largest commercial success and the greatest creative effort in digital narrative have so far been in the area of computer games. Much of this effort has gone into the development of more detailed visual environments and faster response time, improvements allowing players to enjoy more finger-twitching challenges against more persuasively rendered opponents. The narrative content of these games is thin, and is often imported by from other media or supplied by sketchy and stereotypical characters. The lack of story depth makes even wildly popular figures such like the Mario brothers or the Mortal Kombat fighters impossible to translate into successful movie heroes.