wtf am I looking at?

Some other controls:

△ - Motion blur (decays)
□ - Change color
O - Select random visualizer
DPad Up/Down - Change speed
X + DPad Up/Down - Zoom In/Out
L1/R1 - Previous/next track
L2/R2 - Fast backward/forward
START - Play/Pause
SELECT - Exit SoundScope
Analog - Disables controls

lol this works even in optics multiball

I identified the exact bit that enables spawning of a lot of balls.
It just so happens that in your corruption, 0x80 flips the first bit at EEmem offset 0x15FC16 (in NTSC-U), which enables it.

This area of memory probably stores the ball limit in some form, but I'm unsure how exactly.