Wow, sounds... odd? I've never read the books so I'm missing a huge amount of context. Either way, good job on this game.

Yes, it's in English. It was made using a Japanese programming language, but the game is completely playable in English.
Here is how to get around the parts that can't be translated.
If you choose continue from the main menu and you haven't saved a game before, you will get 5 Japanese options starting with numbers. The messages after the numbers mean no data.
In the equipment menu, the first option is in Japanese. It will allways be in Japanese, and it means: nothing. For weapons that's using your hands to punch, and for armor that's no armor.
Other than that, it's playable without any translation.

Have you, or would you consider putting some in-game content that will get the player caught up with the events of the first game and its extra reading material, similarly to how the bk games did?

I don't know if I can put it in the game, but I can write a document containing a recap about Objectives and the books.
About battle frequency, that was part of the Alternative Magic source and that would take a complete rewrite of the game to add in.

Yeah, a recap in a document would be awesome!

Yes, some boosses will keep reviving if you need cash or experience.

I agree with 13. Currently in inequalities and the game is just a tad bit too easy.
Also. Some enemies use items and yet I still get them after the fight. Is that a bug?

one more thing. I am in demise or domination after misteryes of the ainchons. it tells me that gurganchan has new skills but there are no new skills. do you know wy?

That's because the normal punch attacks are unbalanced, and the enemies won't be able to use them soon. Just save before you get into the fight with the ice types, and pack a lot of Life Recovers.

If you're talking about the part ware you have to defend Paid My Dues, just use Tripple Slash on the Robot. That should take it out. I thought I didn't give the robots any Powerbombs. Also, they only do 50 damage. If they're doing 245 damage, that's the wrong type of bomb and I'll soon be uploading a patch for 1.0 that fixes some small buggs and balances the difficulty.

That list is slightly out of date. If you mean the game is giving you an error in Japanese, can you paste the error here so I can translate it?
Just because the sound list says that one of the sounds is missing, that means it was removed because it wasn't needed. Were you able to get passed the robot with Tripple Slash? Another option would be to use a Charm Attack. Since it doesn't have a weapon, it would use normal punches witch are currently way too overpowered. It will kill itself in one punch, and if you're lucky, kill the Blade Knight as well.

After some test playing, I am now fixing a lot of buggs. If you're having a hard time with the game, I'd say go play something else for now because you might need to restart so your copy can reset all the ms (enemy) data. I just checked out Leefox, and other than his attacks, I'd say he's a pretty hard final booss. And no, don't think that you can use Jenny to one shot him. Even he can't be one shot by Jenny! You will have access to her power for the Bioplace, final booss and postgame, but Leefox has too much defense for her to one shot him.
I've found the following bugs in the game. Have you players found any others?
You don't get Erratic Battler when it says you do.
95 percent of the enemies and boosses need redoing (shouldn't take very long).
The Quidditch match in the post... Ah crap, now I guess you know what your first task is in the postgame. Yep, their is an entire area about Harry Potter to begin.