I added netlist sound to sfxphasor, it does sound better, but some of the resistor/cap values were hard to see on the pcb photo.
Is R12 brown,black,red or brown,black,orange?
Is R7 red,violet,orange, or red,violet,brown (orange makes it sound bad)
What are the colors on C6? brown,black,orange? Or is that backwards?
Is C5 100nf like C3?
Are the diodes 1N4002? I don't think this one matters much.
netlist is here: https://github.com/mamedev/mame/blob/master/src/mame/handheld/nl_sfxphasor.cpp
There's another handheld that needs netlist sound, Coleco Galaxian. It has a sound effect when an enemy dives down. Kevtris made photos of the PCB but one capacitor is hiding in the photo, and some resistor color bands are hard to see.
It also has a weird "PUT" transistor that I don't think MAME supports.