key_defs -> keydefs
Drop vagueness from masking names.
setup_movable_items_common -> setup_movable_item
guards_follow_suspicious_player: ‘else’ case probably isn’t one.
byte_81B2 and cohorts seem to be a tinypos_t.
plot_tile: Args are passed in banked registers. Fix that.

Also simplify the logic (the goal in the disassembly should be to show what the game is doing in a C-style pseudocode, not introducing too many high-level elements).