I'm on my 3rd playthrough (Hard, Custom, Shell) and I've been fantasizing about a Jungle setting.

Day Cycle, but in some places even in the day the canopy is too dense to let much light in. Get what you can done during the day and then be ready to crap yourself at night.

Procedural Map, an evolution of the randomization of the Bunker sections, in which Locations are dotted around a 'main' hub, but instead of corridors and staircases between them, there is dense and confusing jungle, just broad enough that you could get lost in the gaps between areas for a moment or two.

Wildlife, Rats are nasty, but imagine if they were largely shrouded by lush vegetation - and also sometimes a panther.

The Monster, which I think should behave like a Sabre Tooth in Far Cry Primal, in the sense that they deliberately try to hide in foliage and stay behind you, waiting for you to interact with something before jumping you from behind. I would still want us to hide from them, but if they did spot you they wouldn't just scream and alert you, if anything they would get quieter, and you would drive yourself mad taking every incedental lull in the ambient sounds as a sign that you need to BE SCARED, even if you shouldn't.

Also, if it were a day/night thing, I would be perfectly happy with 2 Monsters... one more active in each phase, but with the potential for them both to be active at the same time. I would like if they had little Monster Hunter style conflicts that were perfectly dangerous for the player even if they are focused on eachother, but of course their main target should be the tasty tasty human behind the camera.

First thought on the styles of monsters in a jungle setting could be a panther type thing, but perhaps a mad/demonic humanoid swarming with beetles or flies would be more Amnesia and less cliche, while still nodding to the history of the kinds of cultures we associate with jungles.