Yep-- good old "Duck Hunt" from Nintendo worked just like this.
Last night, I swapped out the phototransistor for an LDR (photocell) and was surprised to discover that it was both fast enough to work as the sensor (I figured LDR response would be too slow) and substantially more sensitive... though to be fair, I think I'm using IR phototransistors and really ought to use visible range.. where LDR is more sensitive by nature.
I then stuck the sensor a few inches down the middle of a piece of PVC pipe to act as a "barrel", to shield from "non aimed" areas better and allow for simple aiming, and discovered that with the LDR and "barrel", in a darkened room I could reliably "aim" my "gun" from across the room, approximately twelve to fifteen feet away... PERFECT for a shooting game. In that form, an 8x8 grid could sensed pretty reliably.. workable. Done the other way, minimum resolving power.. with my TV and a dimly lit room with the current code and circuit I could reliably detect a "dot" six pixels wide/high (of a 128x96, 40" LCD display). That's not bad resolving power, and well within workable for a shooting game.
Duck hunt worked like this: Pull the trigger, and it blacks out the screen..takes a read.. flash on only the "duck".. take a read. If the readings differ then the gun (sensor) was pointed at the duck, if they don't, it wasn't. Since it only is functioning as a GUN rather than a tracking PEN, scan rates aren't a problem and the whole game becomes simple to create.
If nothing else pulls me away today, I may re-create Duck Hunt in simple form.... I'm thinking a simple "skeet" shooting game ought to be pretty workable and operate in a similar fashion..
What's funny is that I did all of this a few decades back with Atari 400 Joystick ports, 6502 assembler, and an issue of ANTIC! (or was it Byte.. or Compute.. hmm). For that matter it could have been a Forrest Mimms thing...