There wasn't a prize for the jam; it was more an open invitation to make third-party content for the game, much like many other TTRPG jams (or at least those I've been part of).
I've been careful to not include any official art, names, properties, etc. from the Hollow Knight games in any of my SHELL works, and have done my best to follow Team Cherry's guidance on fan works/merchandise from their FAQ. I've also been very open in all of the legal notices in SHELL that this is inspired by their work, and encourage everyone to go buy their video games, because this TTRPG wouldn't exist if it wasn't for them.
Still, if I ever get any indication that Team Cherry is not happy with what I'm doing, I'll either make SHELL completely free or take it down entirely. Same if I ever heard that Spencer Campbell didn't like that I made a hack of his game RUNE. SHELL has always been a labor of love that tried to emulate the video games I enjoy in a tabletop RPG format with rules I thought would fit the HK gameplay very well.