Paranoia as a game has it's own silliness and style.
I'm assuming the OP isn't interested in recreating that game, so much as the concept that the PCs are that which they hunt. And as such, are paranoid.
I think it'll be more sustainable if the world still is "mostly" human, and the party is partly "non-human" but pretending to be. Then, if each PC is hiding it (perhaps they are of different races and as such, unaware of each others nature).
then, each player is trying to hide their secret, in a mostly human world.
If every NPC was non-human, the cat would be out of the bag after a few encounters (and the non-human PCs would have qualms about this discovery).
But with part of the party human, and part "secretive", everybody has a true enticement to look and act human. And suspect anybody who isn't. Especially when the NPC non-humans are really really bad. You want the majority to NOT like non-humans. Thus, the pretenders have to blend in.
The campaign could go 2 ways:
a) the pretenders side with their brethren in a big party clash
b) the humans could side with their non-human party members
I'm assuming the OP isn't interested in recreating that game, so much as the concept that the PCs are that which they hunt. And as such, are paranoid.
I think it'll be more sustainable if the world still is "mostly" human, and the party is partly "non-human" but pretending to be. Then, if each PC is hiding it (perhaps they are of different races and as such, unaware of each others nature).
then, each player is trying to hide their secret, in a mostly human world.
If every NPC was non-human, the cat would be out of the bag after a few encounters (and the non-human PCs would have qualms about this discovery).
But with part of the party human, and part "secretive", everybody has a true enticement to look and act human. And suspect anybody who isn't. Especially when the NPC non-humans are really really bad. You want the majority to NOT like non-humans. Thus, the pretenders have to blend in.
The campaign could go 2 ways:
a) the pretenders side with their brethren in a big party clash
b) the humans could side with their non-human party members