Actually, one thing I wonder about...
So, it seems the only difference between the 1986 and 1990 versions, aside from the year, is that while both use mapper 2, 1986 probably suffers from bus conflicts (writes to $C00x) and 1990 does not (writes to $8040).
And that the 1990 version has some seemingly useless addition to one routine:
Now, as far anyone seems to know, $4420 is located in the middle of unmapped territory (and from what I understand, bne #$00 is a completely useless instruction).
I don't know if this applies in Japan, but maybe some drugged programmer felt the code needed a drug reference?
(I love how if Love Soldier Nicol's (FDS) protection fails, it branches to address $BADD which jumps to the BIOS' reset routine)
Anyone want to make something of the hex?
AD 20 44 29 E0 D0 00
Edo in 2044?