Feel free to hack! All my work is released under a Creative Commons Attribution License, so you can do anything you like with it, even sell your hack for money, as long as you credit the original.
If you let me know when you release your hack, I'll even share it around my own network. Well, if I like it. But I like a lot of RPGs.
That's really exciting! I'll go check it out.
You can also contact me at lymerpg@gmail.com and at https://dice.camp/@Lyme
One request - could you credit Nightmare Unleashed as by myself and Plasmophage? On a one-page game like this the art/layout are a big deal and very tied into how the final words came out.