Preloaders

When you have a movie that has a lot of graphics and sound, it will create a large .swf file. If you place this .swf file in some HTML and upload it to the Web, and someone with a slow connection comes along to play your game, that person will be looking at a blank screen until the first full frame of your movie has loaded (at which point the movie begins to play). This could take a great deal of time, which might cause your user to become confused as to why he doesn't see the game. It would be nice to be able to tell him, "The game is loading; please wait." And it would be even better to tell him how much of the game has loaded.