Ok, I tried to do some tests while also trying to go through that CG.
I managed to do that, but in a very odd way.
First of all, this bug got triggered from any point in the game.
You could even start from the beginning, and it would occur anyway.
How did I "fix" that?
When the CG was displayed, I did the following things:
1) Opened the main menu (Yes, you could still do that).
2) Selected and opened the item menu.
3) Exit from the item menu to the main menu.
4) Repeated points 2 and 3, but smashing my keybinds constantly until the game decided to trigger the cutscene.
Another odd thing about it was that when the cutscene ended, I was still in the menu with a black screen in the background.
When I exited from the menu to go back into the game, the black screen disappeared right after, and I was in that red room.
When I completed the memory puzzle, and I said that the offering was done, the game froze for a few seconds.
I thought it was about to crash, especially when the audio froze and messed up the game's window size for a few seconds.
Fortunately, it didn't happen, and I was able to get the Sapphire Heart.
At that point, Miji's lines were triggered, and then, I ended up in a permanent black screen.
I couldn't even use that weird trick to trigger the game to move forward because I couldn't open the menu.
That's where I stopped playing, and I decided to write this little essay you're reading.
Personally, I think this hell of a problem might be due to my PC because some effects, like the lights or something like that, used in MZ and MV tend to make me drop frames.
The higher resolution might also impact that.
To give you an idea, the bedrooms, the main hall, and the red room (pre-Sapphire Heart) were the areas where I suffered the most, especially the red room.
This means that this might be caused by bugs related to frame-dropping.
That's probably why you didn't face any issues when you tested it yourself.
But to be honest, I have never experienced this kind of issue with a MZ/MV game this bad (if my theory is correct).
For example, I faced some frame drops while playing Where the Forest keeps the Hollow (another game jam entry), in an area with a cauldron, but I didn't face this issue at all in all the others in that game.
That said, let's start with the review.
The concept of the story was really cool, and I liked the dynamic between Miji and Billy.
I also liked how they both reacted to what was happening around them, and that's why I kept trying to complete the game until this point.
The art was also gorgeous.
The puzzles were a mixed bag.
Some were pretty intuitive, others confused me a little.
One thing I found absolutely annoying and redundant was the presence of the eyeballs, because I couldn't properly explore the areas, and they made me waste time.
Especially when I was wandering around without knowing what to do.
One last negative thing was the save points.
For some reason, I couldn't save at the saint's statue after completing the puzzle related to it, and I remember having this issue at the very beginning (but I might be disremembering on this last one).
This made me waste a lot of time while trying to get to the end and during the testing.