Just read this from the latest version of MAME, released today:
"The microcontroller program for Taito’s KiKi KaiKai was recently extracted. This contains a substantial amount of game logic, allowing the simulation code previously used by MAME to be retired and giving more confidence that the emulation is accurate."
Question for Tux: would it be possible / a good idea/ do you have any interest to implement this in RAINE which, I presume, uses simulated logic for that MCU (and therefore not accurate)?