Varsovian:
Let's say you want to make a game of modern occult / mystical / supernatural horror and mystery. With the characters being mystics, occultists and / or psychics.
Okay, take this in the vein it's meant, which is trying to be helpful:
Is is really, really hard to make a mystery about occultism, magic, or supernatural elements (horror or otherwise) when the Players and PCs are deeply competent and/or knowledgeable in that subject.
Because understanding of mechanics takes the mystery out of the system.
Even setting a 'whodunit' in a setting with "get answers from beyond" powers is
difficult.
Now, I'm not saying you can't do it, just warning you in advance there are a lot of trip points, so carefully examine the powers and lines of info you give the PCs/Players.
quote:
Any other games like that out there? Alternatively, what system could be used to make such a game from scratch?
Depending on what you want (simulationism vs narrativism) I'd say GURPS and FATE are great systems for this. GURPS allows you to get gritty and detailed and set the challenge a lot lower, more in the meat and dstreet level (but it can 'high level play as well) while FATE is far, far, far more loose and GM/Player Fiat narrativism and intrinsically sets better in the "mid-range" power level.