Addition: The sound of the bomb ("mahou" (magical gun) in PH) is probably a human voice rather than artificial. It's like shouting "BOOM" 
So you reproduced the +PCM PCM sounds with PSG? Great. About the voice translation, I am half sure there are other human voices. You know PH bosses behave differently (think of Touhou) depending on factors such as the time until delivering certain damage, which part you destroyed first, died/not died, used/not used bomb, the GR score etc (these are my * guesses *). So some of them would speak under certain situation.
There are frequently used sounds such as gunshots, explosions, bombs, boss alerts etc, so the remaining rarely used sounds are probably special boss voices. Can you pick them out? For the translated voice, you can use Hatsune Miku or something 
Also I am no good at shmups, is there any way to "train" PH for invincibility?
Good news; repair tech informed me he fixed my +PCM and can replace the speaker with an earphone jack so I can record more precisely
Hey, Takamichi I have discovered the way to get infinite lives just send me an email (check my profile/contact on MRC)
just then you'll be able to achieve a very high score more than you can find on youtube (I think the high score on internet is 15,999,999,990) how I did. Well the game allow you to do that but require very high skills is you are not a cheater. 
My High Score:
P.S: The main programmer of this game did a very good job protecting the game against cheaters. That is why I don't wanna share this version. WOW ! This game really deserve a remake on MSX again but without the limitations of the 9938 VDP. Maybe a 9990 VDP version could do it very well for sure and about Hatsune Miku I'm almost convinced to add her voice to the game.
:)
You high score is what the... 
The developer's previous work Kyokugen initially had very sophisticated tap-protection that went too much and destroyed disks that weren't tapped (modified) so he had to release a patch to nullify that. Yes Hatsune Miku is a gorgeous chick but she isn't a cheap woman and costs 13000+ yen However demo is valid for 39 days.
@Takamichi: Pleasure Hearts INFINITE LIFE emailed.