You ran out of room in your PM folder for "Consolidated Response 3", so here it is:
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CONSOLIDATED RESPONSE 3
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Also, note that you can get false positives by stepping on non-button positions that activate the same rows and columns as an actual button positions. The MCU will think that the non-valid positions are not actually happening (because no buttons are there) and pair up the columns and rows in such a way as to make them correspond to valid buttons (which you are not actually stepping on).
To solve the problem of the above two paragraphs, I think you should get a thicker board and drill large holes into it and place photo receivers in there. Then you can use the light/darkness of the photo receivers to reinforce the beams. This requires some light in the room that you are playing however, and you need to get photo receivers that respond fast (photo-diodes).
You can actually use this photo method to reinforce the beam method (you only need a photo-receiver in the valid positions).
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The part that makes all previous parts irrelevent
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But if I were you, I would scrap the whole beam method altogether and instead just use the photo-receivers. Less processing involved, more durable (can't side swipe the beam sensors) and you can make an individual sensor for each pad with less parts than making a "ring of beam sensors" around each arrow. 4 photo-diodes as opposed to 32 beams each of which is much more expensive than a photo-diode. The only requirement is you need a certain amount of light in the room and the sensor MAY activate before your foot actually reaches the ground depending on the dark/light threshold you have set it to.
To read about sensitivity and speed of photo-transitors and photo-diodes, go here (there is a tradeoff between speed and sensitivity, but too much sensitivity isn't needed for your application).
https://en.wikipedia.org/wiki/Phototransistor
Stupid 5000 character limit.