sub_CA81: Simplify play_speaker call.
reset_something -> reset_position.
byte_81AA -> stashed_A
Rename word_81A4/6/8 -> saved_Y/X/VO.

It's a vague set of names for now, but better than the anonymous word_*.
Add door position masks.
Reduce.
Rename sub_CA11, sub_CA49 -> move_character_Y, move_character_X