Windows (which I assume you're using as this is a Windows-only game) is able to open a given file for you when you double-click on it because it inspects the file TYPE, as indicated by the extension, and has a stored list of default programs to use to open each type. It tosses the file to that program, and you're on your way. This is a great system in general, but it has one shortcoming: what if there were files you might want to open in more than one way?
The datacrystal file is a .js file, meaning javascript. This is because RPGMaker MV is built out of Javascript: the .exe you run just loads a bunch of javascript. This allows it to be easily customized with plugins ALSO written in Javascript. These plugins are loaded when the game loads and immediately integrated into the rest of the code. Thus, if you want to get additional data INTO an MV game, the easiest way is to just create a dummy "plugin" with no code, only data, which then becomes immediately available to the running program. This is what the datacrystal file is, and how it works.
.js files are generally code, so Windows assumes you want to RUN them when you double-click on them. This is a reasonable assumption, but useless with the .js files associated with MV, as 1. They're all designed to run only in the context of the MV framing executable 2. They're all fragments, not complete programs 3. The datacrystal file doesn't even have any code to run, just data and most importantly 3. In THIS case, you don't want to run it anyway, just edit it.
But Windows doesn't know this.
You need to TELL it this. You can do this in any of 3 ways:
1. By RIGHT clicking the file, choosing "Open WITH" instead of Open, and choosing Notepad. If Notepad isn't an option, you will have to select "choose another app" and direct Windows to Notepad in the resulting dialog.
2. Because Windows realizes .js files are also just text files, you should be able to also just select "edit", which should also open it in Notepad.
3. By simply opening Notepad on its own (Start Menu, type "Notepad", click), and drag-and-dropping the datacrystal file into the program.
All of this is why I specified "Open with Notepad" in my initial post.
Once open, you can edit and save the file. HOWEVER, be careful. Notepad likes to default to saving things as .txt files. Be sure you're saving it as .js, overwriting the original. To be sure, re-open the file after you THINK you've saved it, and verify the changes are there.
I've also been struggling to get this cutscene to trigger. I reinstalled a fresh save, and changed the datacrystal file before first launching the game, it now looks like this -
MezzStatus = { NumberofBoarDefeats : '3', ChaptOneTrainedEnd : '1', ChaptOneDelta : '12', TimesFucked : '1', TimesOral : '9', TimesAnal : '0',}
visited the island and returned to haven, walked past the alleyway, cutscene did not trigger.
1. Verify that the changes were saved correctly.
2. Where is the changed file located? Is it in www\js\plugins, as the instructions said? Changing the datacrystal.js file in the main directory of the game and failing to move it will not do anything.
I tested the most recent release by directly modifying the file to exactly the contents you listed below, and it correctly triggered the start of the scene ("!" icon and crash sound, which you then have to investigate further.)