Frequently blocks off routes to backtrack, closing doors permanently, dropping you off ledges you can't climb back up, etc. Essentially denying you from retrieving things you didn't get earlier.
The first video game about Backtracking denied was released on November 14, 2008.
The Molasses Flood has published all these games
On other hand this is also used to funnel the player forward, essentially telling them they have nothing left to do in the previous areas and shouldn't bother wandering back to them, making sure they don't wander too much pointlessly.