Though I've given away the solution to some of the early puzzles, each one does increase in difficulty. One of them involves solving a QR code. One of them involves slowing down audio and then translating it. One of them involves watching creepy video. Many require cracking codes, knowing different languages, visiting specific websites and finding a hidden message, checking constellations, using chemistry, using music theory, and more. It's insane.
This looks like an obvious passion project by a very smart person. It reminds me a bit of the early text based adventure games but in this case it was created by one person in their spare time. I would have been completely obsessed with this when I was 14.