Lensing is one of six creative constants that apply to all videogames. It refers to distortion of information, like light passing through a lens, between the player and the game. The constant creates two kinds of boundary.
The first boundary is the effect of looking at a game through a screen with limited control and haptic feedback (such as rumble) to work with. Effects like monocular perspective, a lack of peripheral vision and disorientation all play a part in what the player really sees or understands (as opposed to what the developer thinks they should see). Through the lens of limited information, the player needs to understand the wider world of the game, and so there are certain kinds of information that do not translate well. Lensing is why games often have to be obvious.
The second boundary is the consequent response of the brain in pressured situations, and how it lenses information to only read that which is considered most urgent. Under pressure, the play brain's focus tends to dominate over the art brain and enter a state of flow. The game becomes more of a frame and less of a fantasy as the brain concentrates and lenses binary information based on its endogenous value in the moment rather than its narrative value or supposed meaning. In more stressed situations, this effect even involves the lizard brain and its anxiety response mechanisms.
Lensing is why uniformity and classes are important. They allow the play brain to break down the information quickly and form strategies accordingly. So videogames tend to be much more literal and task-driven than boardgames or tabletop roleplaying games. Lensing is also a key factor in why videogames are not a good storytelling medium, but a great storysense medium.