Johnny Impact said:
Ravenloft. Always wanted to run a horror game. Going to have a chance to do so in a couple months. Currently plowing through the sourcebooks. Even choosing video games for inspiration -- Dead Space 3, Dark Souls, Black Flag.
I'd be careful with Ravenloft. With long experience I can tell you it tends to work best as part of another campaign, with the PCs stepping into the mists occasionally for an adventure, either as the result of being randomly sucked in, or with someone providing them with a "Scroll Of Return" or knowledge of an oh-so-rare portal and sending them on a mission.
The reason is that each domain is a self defined cosm with limits that can be controlled by each particular lord, many of whom hate each other, and keep everyone locked in or out. What's more most of these dimensions within the pocket dimension have their own rules, and many re-write the minds of the people inside of them to conform with that domain's sense of history and reality. The idea being that if your in Ravenloft too long you become PART of Ravenloft and furthermore part of whatever realm you happen to be in at the time. Or at least that's how it used to be when I was using it. This is how the game explained how say you might have some guys in one place with a thriving Egyptian-themed culture and another place where everything is based off of Hollywood Translyvania. With rare exceptions these areas are set up to have no contact with each other which is how you deal with the question of why the Dark Sun based pocket doesn't say conflict with the Victorian-type pocket, or a band of Half Giants don't say wander in and drink Strahd's milkshake since their stats are so much higher than his (Strahd can be taken down, and is intended to be beatable by a group of regular 10th level characters in most adventures, even with all his tricks for example, doing so is the subject of the many, many, reprints of "Castle Ravenloft" which started this whole thing, and there have been domains created for much higher level threats). It's also why say you don't have lengthy cosmological discussions between guys from Krynn, Greyhawk, and The Forgotten Realms all meeting since nobody remembers where they are from for long.
As a GM this becomes a pain in the arse because fundamentally each domain is an adventure, with a pretty straightforward "discover who Foozle is and then kill him" plot. Once foozle is dead, that section of the pocket dimension then disappears and the PCs either get returned to their respective worlds (classic module type Ravenloft) or get bumped into another domain for their adventure. The problem of course being that at this point everyone's minds are thus going to re-write themselves. So let's say you start a game at level 1 and they kill some domain run by a horrific goblin lord, by the time they have done a few adventures they literally won't remember anything that happened back then, growing to believe they have always been in whatever world they are a part of. Kill Strahd, a week later (it might be longer, it's been a while) if your still in Ravenloft your going "Strahd who" and if you've say been in some Egyptian setting plagued by a mummy lord you think your an Egyptian-type guy, and everyone needs to re-work their background beliefs to explain who they think they are.
Also unless they changed it the GM tends to be encouraged to screw with the PCs in a "catch 22" fashion, which can be fun for a while, but gets annoying especially for the players. Basically if the PCs act immorally they become corrupted and eventually wind up getting so many horrible mutations and gifts that they become lord of a new domain and go on to NPC-land (ans since they can't leave they would be hard to play anyway), on the other hand if the PCs don't behave badly the mists, this being the demi-plane of psychotic evil, punishes them as opposed to the previous "reward" so the more good they are the more horrible things the GM is supposed to do to them (and by this I don't mean tempting them to evil) as the world literally conspires to screw with them. This means your either doomed to be a villain, or to eventually face rather arbitrary character assassination in a prolonged campaign.
I'm just saying put some thought into it, I've seen this go wrong a lot, including when I've tried to GM ongoing campaigns using the setting. It can be hard to get rid of some of the odder mechanics because when you say remove the amnesia/belief rewrite thing it becomes harder to justify how all these little cosms exist and don't influence each other in the cases where the lords leave their borders open. Strahd and Azalin sending armies against each other is one thing, but it gets far weirder.
At any rate all rambling aside, if your looking to play video games for inspiration there are actually TWO Ravenloft games, "Strahd's Possession" and "Stone Prophet" both of which might be public domain now or on various cheap old games sites. Both use the whole "visitors" things where you play a couple of adventurers from The Forgotten Realms who wind up in Ravenloft with the eventual goal of curb stomping the local lord and leaving. There is a very loose connection between them. The first game is pretty much the regular Transylvanian "Ravenloft" setting which includes some bits from classic versions of the module, the second involves the Egyptian realm (the name eludes me off the top of my head) and instead of a Vampire Foozle is your basic super-powerful Mummy guy.
If you can find it Dungeon Adventures magazine had a Ravenloft adventure I quite liked and ran a couple of times, sadly I don't have my magazines anymore to give you the specific name but there might be archives of them around on the internet somewhere. It involved a very small domain, a haunted house, where the "Lord" was actually an intelligent evil sword as opposed to a traditional monster. Which was an interesting spin on why the protagonists can't leave the haunted house (pocket dimension borders in the demi-plane sealed by the "lord") and the PCs figuring out they were ultimately up against an item with specific "to destroy" requirements rather than a monster which could be confronted traditionally. The adventure was designed whereby one PC would be the previously unknown heir to an estate, and when they enter the estate they wind up passing into Ravenloft via a curse. It can be clever since it doesn't necessarily require any keep knowledge of Ravenloft or the PCs to know why they are facing what they are, but some savvy players might guess if it's not mentioned when they look outside the windows and see only mist. Of course the nature of that adventure is that since it's a curse, once the sword is beaten and the intelligence banished they return to their normal world, and are in an empty (though very nice) house. Typically they aren't going to be around long enough (either killed or having won) to worry about long term Ravenloft exposure nor around long enough to really worry about mutations/gifts or slotting off the "malign intelligence" of the place through routine do gooding, unless some dude pulls out a Holy Avenger which always get attention if I remember because those are one of the few good artifacts that still work and it's like a lightning rod for attention getting, but the odds of anyone having one of those is usually minimal.