Quote Originally Posted by blackmage_nuke View Post
Gameplay wise I know you have to lock them all to get the secret ending, but Ive wondered since KH1 what locking a world does plotwise, the first time I locked a world I thought it was closing the barrier, which would stop the heartless getting through... right? Nope heartless still showed up, so Im confused as to what it actually means to lock a world.
I don't remember KH1, but the point is to prevents the Heartless from ruining/consuming a world in the same way that happened to Destiny Islands.