if you byteswap the P rom you can read all the text from the game:
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BRING THESE MEN TO HELP. (Girl in intro)
COUNT YOUR BLESSINGS... THAT I BEAT YOU ! (first boss)
YOU IDIOT ! (first boss)
GO TO THE LOWER WORLD WITH ME ! (pretty sure I never saw this text
WHO ARE YOU ? (boss 2)
NO ONE RETURNS ONCE THEY .. HAVE STEPPED INTO THIS WORLD ! (boss 2)
GO YATSUFUSA ! (boss 2, talking to her dog)
IDIOT... (don't remember seeing this ingame... could be wrong tho - so short)
YOSHITSUNE IS HERE! (level3 boss)
I'LL TURN YOU INTO SWORD RUST. (level3 boss)
WATER DRAGON GIVE ME YOUR POWER ! (level3 boss)
NO ONE CAN STOP OUR SCHEME. (dont remember this ingame)
DON'T STAND IN MY WAY ! (last boss)
I WON'T DIE UNTIL I HAVE IT ALL ! (last boss)
LET NOBODY INTERFERE WITH ME / HAH HAH HAH (cutscene post level1)
I WILL TRAVEL INTO THE FUTURE .. TO KILL YOU THERE ! (don't remember seeing this)
YOU HAVE TANGLED WITH ME ! / I WILL DEFINITELY KILL YOU ! (cutscene between level 2+level 3)
I DON'T WANT TO SEE YOU AGAIN .. I WILL KILL YOU MYSELF ! / BRING HIM HERE !! (cutscene post level3)
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unless I've screwed up when I had a super fast playthru - there's tiny bits of unused text in there at least, in amongst the boss quotes - quite odd really...
you can also see a little bit of text referring to STG + ACT in the P rom too...
debug dips also do stuff - haven't had a lot of time to investigate it properly but pretty sure I found invincibility codes and debug screen output along the way...
\o_