Having a parallax background produces a three-dimensional effect in a two-dimensional state (Kelly, Patton, and Martin et al, 2014). To achieve this, I created a variable background which included elements such as randomly selected mountains and trees. This improved the depth perception and can help the game feel more immersive to the player (Zhang, Yin and Florêncio, 2009).
Kelly, B., Patton, S., Martin, S., Lyons, M., Ang, R. and Hedrick, R., Bally Gaming Inc, 2014. Gaming system, method and device for generating images having a parallax effect using face tracking. U.S. Patent 8,721,427.
Zhang, C., Yin, Z. and Florêncio, D., 2009, October. Improving depth perception with motion parallax and its application in teleconferencing. In 2009 IEEE International Workshop on Multimedia Signal Processing (pp. 1-6). IEEE.