Driven Mad (and to Level 2) By The Revelation: Cthulhu-style Investigative XP Mechanics

 For a while I've been brainstorming a Lovecraftian/cosmic horror investigative sandbox campaign for lotfp/bx. Basically, the idea of 'What if when all leads turn up with dead ends in a Call of Cthulhu campaign, instead of having stuff like IDEA rolls and the like, you had to just drop the investigation and come back to it when something clicks or when you find some new information that helps you progress?' Like real investigators do irl. Like how a lot of serial killer cases get dropped for potentially years and then sometimes reopened when they find something new, or somebody ends up on the force who has a new perspective that pulls it all together. 

Of course, I don't want to use actual Call of Cthulhu for this, because CoC is way too complicated for my tastes, so I've been looking at adapting it to lotfp/BX, using some mechanics from the fantastic OSR Mythos rpg Silent Legions. lotfp/BX's base XP mechanics, of course, need to be modified for this sort of context, since Cthulhu investigators aren't usually robbing tombs and pulling out fancy loot. You don't see that sort of thing much in Lovecraft, or even his more adventure-centric imitators. At first I looked at the XP mechanics in Silent Legions but I didn't really like them because it's just kinda... 'You get XP for showing up to the session, and get some more XP if you do good shit', which is one of my least favorite ways of handling advancement. So I hit the books and started poking around with my own XP system for this style of investigative Lovecraftian horror sandbox thing. 

These rules assume that the average Investigator is levelling at about the speed of an lotfp/BX Fighter, so 2000 XP to get to level 2, with the total doubling each level. So with that out of the way, here we go:

• 500-1000xp for a completed investigation. The case solved, no more no less.
• 200-300xp for a crisis averted. The horror in this particular investigation has been stopped or slowed down. The cult has been thwarted, at least for now. What counts as 'averted' is a bit malleable, since these types of characters rarely fully succeed. For a general litmus test on what counts as 'averted', the ending of The Dunwich Horror is a crisis averted. The immediate horror has been stopped, even though the town of Dunwich is still pretty much in the thrawl of Yog-Sothoth and this shit is probably going to happen again. The Horror at Red Hook is also a crisis averted, and you could honestly argue that At the Mountains of Madness is a crisis averted too, since Dyer gets his paper out there and potentially stops the impending expedition, although that one's a bit less definite because the text never specifies if the expedition is prevented, because the story is Dyer's attempt at preventing it. The Colour Out Of Space is solidly a crisis that isn't averted. The Gardeners are obliterated and the blasted heath rises from the hills, expanding slowly outwards. The Thing on the Doorstep could go either way, depending on how you rule it. 
• 100xp for new alien species encountered. If you encounter the Mi-Go or the Elder Things for the first time in an investigation, for instance, you get 100xp, assuming you survive your encounter with them.
• 100xp for each Mythos tome recovered. If you go into a cave and chase out some cultists and steal their copy of the Pnakotic Manuscripts or Coultes de Goule or whatever, you're getting this xp. If you already have a copy of said tome though, you're probably not getting xp, unless you couldn't read the copy you already have and this is a copy that you can read.
• 50xp for each person in significant danger saved. This caps out at probably about 500xp. If you save an entire town, you're not getting xp for each person. You're getting 500. Otherwise, it's 50xp per person. Possibly Upton could get 50xp in The Thing on the Doorstep for (arguably) saving Derby's soul by killing his body while Asenath was occupying it. Depending on who you are though, this might not count. It's up to you.
• XP-as-treasure for eldritch artifacts recovered. If you find a Cthulhu idol, you're getting xp for it, based on what it's worth. If you find the Shining Trapezohedron, you're getting xp for it, as you'd normally get in lotfp/BX for finding treasure. Given the rarity of these kinds of finds though, this isn't nearly as significant of a portion of your XP as it would be in most old school-type games.
• You don't get any XP for killing enemies in this system, since Lovecraftian horror is typically a much less kill-y genre than Weird Fantasy and Swords & Sorcery, and since PCs are generally much less well-equipped to kill anything except maybe a couple of cultists here and there.