most important to my current efforts are "pos x", "pos y", "line top", and "line btm".
SystemID O2
0005 b u 0 PPU pos x
0004 b u 0 PPU pos y
0A b s 0 Main RAM spd x
0B b s 0 Main RAM spd y
0C b u 0 Main RAM line top
0E b u 0 Main RAM line btm
0D b u 0 Main RAM dir facing
02 b h 0 Main RAM ig-timer