ok, im noting some objects apears and desapears randomly.
it may be something to do with the servers, or not.
also, there is not a "center of the map".
where are the other 6 online servers?
Its random. Its to get you to start noticing that things are changing, and sets you up to find the hidden ending later.
Also, the dev's message about his friends running out of bullets before beating the game is likely a hint telling you you need to shoot something. So far, the rest of his message about the 100% save file is just filler to make it look like a method you might use to load the save file on an older computer (which isn't entirely incorrect, its very close).