Diagetic vs. non-diagetic game displays

The method used to display game information, either overlay or in-game, in first-person shooters, likely has a measurable impact on player performance. Quantitative research is needed in this area, as game designers are pushing for heads-up displays to be as minimal as possible. This is especially important for the smaller screens (such as tablets and even cellular devices), which are now being targeted by this genre. Quantifying the effect of information displays across different screen sizes (small as well as traditional monitors and TVs) will allow for interfaces which improve the user's performance and gameplay experience.