IDK if this was a bug due to the dpi scaling(which was a bitch to get running with their version of locale emulator, had to remove the dll and use my own to prevent cashes), but I had no character models(are there any? or is this more like an NVL style?). Speeding though skip mode and finally choosing the right option to advance the story unlocked the gallery, but unless all the audio is uncompressed, the size of this game vs the image resolution is crazy, especially since the whole thing is compressed into its own file.
Saves are also weird but stored locally in the folder, so a local version of this game with a fully unlocked gallery is technically possible.
If you have issues launching, make sure it's not running in the background, delete the locale emulator dll(use your own method of locale emulation) and disable the scaling in compatibility settings.
Expanding on the no images, I still got backgrounds and occasionally scenes like this in the OP but none with both lime and lachis in the same place talking to you. Game also crashed if it started the vn story with the old locale dll so it might be something to do with a borked install.