The short answer imo is to use a separate camera actor for the game type, for example a Beat Em Up, SideScrollers, ShipScrollers. This Camera Actor is essentially the dungeon master and more less controls the game. It moves parallel to the player as the player moves (usually in Y + in most cases I have used it). Put a blocking yet invisible box collision far left and far right on the CA and it will quite literally stop your player from advancing. For example in a Beat Em Up game, you move right untill you walk upon a few thugs, camera stops, and now you must defeat them in order for the camera to keep moving and progressing. While I have talked much about the concept through the years, the most recent and best example imo is the thread I made about ShipScrollers. I think you can find the camera information you seek there.