When I first started playing Rez, the screen was a flurry of light and color. I could guess what things should be shot at but I was mainly shooting things randomly and seeing what would happen.
It turns out that Rez tracks several metrics for each completed level and these are key to progressing in the game. The "Analyzation" metric notes how many "layer levels" of any level you've unlocked; you do this by shooting something called a "password lock". It consists of a little satellite holding a rainbow prismatic cube; shooting the satellite releases the cube, which must be shot eight times to proceed to the next "layer level". Missing one of these cubes when they appear negatively affects your "analyzation".
The other important metric is "Shot down", which notes how many enemies you've killed; HOWEVER, only enemies that "spawn from nowhere" actually really count. Enemies that spawn from other enemies do not affect your shot down total and may be safely missed unless they are projectiles which directly threaten you (slowly home in to your location).
So when you have a flurry of shit flying at you on the screen, suddenly target discrimination becomes key. So you have to pay attention to the objects on-screen and decide whether each should be shot or not, if it's worth the effort to swing your targeting reticle over it.
Then I reached a point in my Rez play where I was not paying attention to the targets but rather keeping it focused over the entire screen at once, noticing everything but zeroing in on nothing -- deconcentrated attention. And then it became no longer about aiming to shoot things down; enemies seemed to materialize directly under my reticle waiting to be hosed down.
And then things got really weird. I was watching the screen, but also observing myself playing the game. It almost seemed as if a different person were at the controls, a person which I still knew was me. I was thinking and reacting faster than I could understand what I was doing. It was akin to a mystical experience, one sought after by many in temples, abbots, and ashrams, brought within my humble reach by a fucking video game.
And people wonder why I'm a gamer.
To this day my copy of Rez remains a treasured possession, and playing it has shown me many neat things about what I'm cognitively capable of.