Full system conversion experiment

I wanted to run a horror game in October, so I'm trying an experiment to see if I bend my action narrative resolution mechanic to run a very different genre. The real simple version of the system is it's a skill check system where you roll once to represent an entire encounter, and then players take the lead on narrating the story to fill in all the details of the one giant dice roll. To try and do horror I changed all the supporting systems/skills/goals and replaced them with more genre appropriate ones.

I had a couple ideas I thought were clever and typed up a prototype today.

I don't know if it work, but I think this kind of experimentation is both fun and maybe it will teach me something.

Anybody here ever work on a full conversion? I created my game to begin with because converting d20 games wasn't giving me what I wanted. I never got a full conversion further than prototype for any system. Curious what other people learned from trying something like this.

If I were building a horror game from the ground up, I don't think I would use this resolution mechanic, I would probably aim for something that felt more reactive. Horror is really tough genre, and I think disempowerment and bad things happening to characters are tricky to make work in all games, and especially shared narrative. It's probably outright impossible to scare my friends sitting at a table as a group, but I'll settle for telling exciting stories with the horror tropes.

That's my hypothesis anyway, going to try it out and report back. Really want to hear about other peoples experience doing conversion design or any ground up horror design.