During Halo 3 user testing, researchers at Microsoft Games Research Labs used a breadcrumb marker that was “dropped” by each player every few minutes. Each one was a different color and reflected their position on the map after fixed intervals of time. Early tests showed that a lot of people were getting lost on the very first level and many players were ending up back where they started from. To fix this issue, designers added one-way boundaries in the form of cliffs that they dropped down, to ensure that players weren’t able to backtrack. Needless to say, players who got lost very early in the game rated their game experience as very bad and some of them expressed their willingness to quit playing.
Thompson, C. (2007). Halo 3: How Microsoft labs invented a new science of play. Wired, 15 (9). Retrieved here: http://www.wired.com/gaming/virtualworlds/magazine/15-09/ff_halo?currentPage=all (Featuring Randy Pagulayan)