I Finally got it working. Took me several hours to figure it out with trial and error. The instructions and other peoples post didn't exactly help everyone says something different and non of them seems to help. Ill give you step by step and a better explanation of how to get this game installed correctly as intended (maybe). Dont worry it will work. I have windows so it will work if you have windows. I don't know about any other platforms. Scroll to the bottom if you to know where save files are located.
First you need to download the all in one of the game above. If you dont see the game go this link.
https://f95zone.to/threads/itazura-gokuaku-v2-10-real.24472/
This will send you to the download page for the game. You can download game in parts too but you would have to merge them. Im not gonna get into merging the game. The last game i did it took me a day to figure how the merging process worked.
Once the game finished downloaded. You want to make a new folder for it and put the extraction in this folder. You can put this folder anywhere. Best to just put it on your desktop.
Before you do anything else install the Locale Emulator 2.5.0.1. You can download it here.
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Get this installed. I think the process was simple I forgot. But there are tutorials on it do use those.
In the folder you created. Open it and extraction the game files. Open folder "Mischievous vampire" - "1 - Installer" - click then right click on "IHSetup" - "Locale Emulator" (if you dont see this option, means you haven't installed the Locale Emulator). "Run in Japanese or Run in Japanese (Admin)" (note keep it consistent). "Yes" - "ok" - Install "DirectX" (the game will not run correctly this isn't installed, its easy im not going explain the installation for it). On the game setup screen choose the second option. Get to the install screen. Dont install yet. Click on the option to change where to put your download (its important). Its like the top button of this screen. Click it, "This PC", then click/Highlight the "windows C drive" and confirm/apply that is where you want to put it. After click the left button (install button).
Right click on "2 - update 2.10" - "Locale Emulator" - "Run in Japanese". Change the dictionary again. "This PC" - "windows (C)" - click on "Gokuaku" - "ok" - click install. Password is in the "instructions" ( if it ask you if you want to replace the existing files click yes on everyone of them). After its installed run the game application from the fold "Gokuaku" (the one you created in windows c drive). Get to the game menu screen then exit the game. Next install "3 - HF Patch for 2.10" - "Locale Emulator" - "Run in Japanese" - "yes" - "ok" - "next" - "next" - "browse" - "windows c" - "Gokuaku" - "next" - decide what you want on the option then keep going till, then install it. That should do it.
If your getting a lot errors or something. Or failed to install it before its best for you to delete the previous installs and data. Windows c drive, view tab on the top of file explore check hidden items. Open user data, ( name of your pc) , AppData that is grayed out, roaming, REAL ( this is where you put your saves). I dont know this has anything to do with errors but i had error before and deleting this helped me reinstall everything. This is where your saves go im sure it doesn't effect the installation. Thats all i can tall you. Thanks for reading this long article.