Hey, so I'm normally one to lurk but I got curious about this one and thought I should put this here...
The game is built on this software called Twine...
At that, an older version (current is 2.5.1, the version used is 1.4.3)
But let's get to the main part!
I found this easily by opening up the .html file in a text editor and found it used Twine version 1.4.3 with the Sucarcube Story Format. (I know that might be confusing, just don't worry about it)
Initially, I looked up what Twine was (you can too if you're not familiar, it's basically a choose-your-own-adventure game creation software) and downloaded the latest version.
Now, it does have an import feature where you can import built HTML files/games, but when I tried that it didn't work...
After much searching, testing, and playing around I eventually found and downloaded Twine version 1.4.3 and tried to import the game and... it worked! The whole game was laid out in front of me!
Now, it's not over yet!
I tried "testing" the game (as Twine has a "Test" feature) but it just flat out doesn't work... It messes with the page formatting with additional debug(?) stuff...
But if I built the game fully and put it next to the folder full of the images (like it is when you download it) and it worked perfectly as if nothing had changed! (If you run it by itself, it just doesn't load the images but otherwise seems to run fine...
Now, I'm no coder and definitely no artist but I thought I would put this here to give whoever continues on a head start.
At that, it looks like super easy code. Even with my almost zero coding experience, I could probably do the coding for the game...
But if someone really wanted to continue this game even if they didn't know about coding, it probably wouldn't be too hard to learn the language that twine uses. (And kind of figure out what is happening with the code already there)
But anyways, like I said, though i'd just put this here and share my findings to hopefully jumpstart someone else!
Edit (While drafting this message): I found that when testing, there's a "Debug Panel" to disable toe debug text that appears when testing. It can be hard to get to, though, but you can try to change the zoom level in your browser and change the size of the browser window it eventually gets to a spot where you can access it.
Edit 2: I should also mention the game is actually very stable, it just kind of falls apart when you get to the unfinished parts...