I would like to help, tho not sure how yet. But arent you able to look into the game's files to get the images?
I'm afraid it's not that easy, you see, Cloudnovel doesn't let you host images on their server (unless you pay them lol), so when Tunner was picking the images he was gonna use for the vn, instead of reuploading the images on something like imgur, he just didn't bother with that and just used whatever website they were being hosted on, which essentially meant that if that image was ever deleted from said website (e.g. Mairusu's DeviantArt) it would've also been deleted from the comic, which is what happened with like half of the assets from that thing, (and it's also why it doesn't work).