BUT!!! You should not make your artwork as big as such since that'll make your game just slow to render. You have to slice them to smaller sizes so that you can turn on/off when they are visible/invisible. Think of Google maps. They don't load all the possible tiles for the world. They just load what you are looking at and load as you pan/zoom around.
So what do you think if I make a movieclip to contain the world about 4000 x 4000 pixels and inside that I put the enemies, items, etc. I am trying to make a platform game using this engine: http://www.kongregate.com/games/Syle...utorial-extras which I have upgraded considerably. Does this sound like a good idea?