I'm playing the video game Alien: Isolation. It's very well done and I've been thinking about how it would work as a tabletop RPG. Now, the easy answer is that the exact translation wouldn't be all that great an idea--after all, Alien: Isolation is single-player, it's not necessarily a fun experience if you can't re-start, and depending on the initial information, you'd very likely have the Amanda Ripley character thinking: my job is to get guns or something to kill this thing (instead of the video game's explicit "you can't kill it" information).
That said, we're talking about a game like Alien: Isolation that has the player(s) creeping around hiding from a super-predator they can't beat.
The Stealth Drama
Observations have been made that if you have to make enough X-checks (Stealth rolls), eventually you're going to miss one. If the penalty is death, a series of 12 Stealth-checks (or whatever) is simply the hail-marry of your character's life-cycle. If that's how you run the hunt, either the Alien better be blind, Ripley better be a ninja, or, if it's even an 80% favorability of Ripley, she's likely a goner.
I wouldn't expect that kind of thing in a game unless I'd either signed up for it--or screwed up badly (usually meaning taking a known risk: "Sure, you can try to stealth your way past the super-predator--but it's gonna be like 12 Stealth v Perception checks and you're good--but it's got a 16 perception roll so ...").
Note, for the record, in that case the GM has explained everything material and I can figure out what my odds are. At that point, if I decided to go for it, cool.
The Use of Dramas
The core concept behind Dramas in JAGS is that instead of one roll (or one roll-vs-roll) you make a number of rolls and you get to "take actions" between them to improve your chances. In this case, the idea is that I'm going to be making Stealth rolls and I have to take actions to make that work.
The Basic Drama: 3-Roll vs. The Starbeast's Perception
Star Beast was the working title for Alien. Here's my thought for the basic drama architecture. The creature has a prey-sense of, let's say, 16 or less. I make 3 rolls (the "typical" drama is a 3-roll drama) with a Target Number of 16 (meaning if I have a 14- Stealth, I have 3 rolls to get a cumulative success number of 16+ and failures result in 0).
Let's further assume that these rolls indicate movement. If I hold still and am concealed (like inside something) the Alien will automatically miss me. If I am completely uncovered in its line of sight, it auto-sees me and kills me. But the general situation is that I am moving through a mapped environment and I get one Walk/Run/Sprint move per roll. The movement type adds or subtracts from my roll.
- Walk: +0
- Run: -2
- Sprint: -4 (in the game, sprinting is death if the Alien is on your floor)
If we assume Ripley's Stealth is 14- L2 (meaning she's very stealthy for an average person) she'll walk carefully everywhere, roll three 10's on average, get 12 SP's, and get seen an eaten by the Alien.
The game adds the option of crawling, though. There are no explicit rules or crawling in JAGS--but let's say that Crawling gives you 2 yards of movement per roll (about half of a normal Walk score) but gives +2 to each Stealth roll. Ripley now has a 16- Stealth score for each roll if she crawls: her average roll will get her 18 SPs and she'll be safe!
The problem is, of course, that's not reliable and, also, if she makes noise (combat, opening doors, whatever) then the Alien starts looking for her. If the Alien suspects she's there--let's say she gets within 2 of it (so if she only makes it by 17 or 18 or something happens like she has to shoot someone) then it starts looking and it gets a roll to re-set the Target Number for a while. If it rolls a 10, nothing changes--but if it rolls less than a 10, the difficulty goes up by the number less than 10. Let's assume that its hunting doesn't make it's Target Perception worse, though--so she has a 50% chance of no change--but a chance of the roll going up by one or more.
A Success Point Pool
In the game Amanda Ripley cries out for some kind of Trait (probably a Character Point trait--but maybe Archetype Trait that helps her with Stealth). Firstly, she's unlikely to have formal training in Stealth (she's an engineer)--but she's small, quick, can move very quietly. Let's call this "Sneaky," charge 4 CP for it, and give her 4 Success Points that can only be used for Stealth Rolls and recharge every "scene" (level of the station, in this case).
This means that Ripley can fail by up to 4 one time per level and not get eaten. This gives us some buffer for failure--it also gives us some drama if these get eaten away early on in a level.
Secondly, let's give her some actions other than crawling.
HIDE: If the alien is "looking for her" meaning her last drama only beat it by 2 or she made a noise of some sort, she can choose HIDE which is non-moving, requires a hiding spot within [Move], and then doesn't move her for the rest of the drama. It gives +4 SPs to the roll she makes to HIDE. Furthermore she gets to keep her score while hiding--so the Alien will probably give up.
Example: The Alien is looking for her after she shoots an android. Roll one, she has a 16-, rolls a 12 (+4 SPs). But the GM makes the Alien's Perception roll on the table and it rolls a 6, making her new Target Number: 20. She elects to take her 2nd Roll to Hide.
The map / GM determines the hide spot is within 4 yards (+0 Walk) so she declares that and gets 14 (Stealth) + 0 Walk + 4 (Hide) = 18-. She rolls a 10, +8 SPs.
She is now at 12 SPs--but needs 20 or it sees her. Her roll is another 18- for remaining hidden--but not moving. She goes for it, rolls a 12--that's only 6 SPs. (she keeps the roll she ran in with--so running to hide kind of defeats the purpose). She ends the roll with 4+8+6=18 SPs.
She spends 2 from her pool to avoid being eaten!
DISTRACT: She can throw expendables (flares, cobbled together noisemakers, cans of food?) to make a noise somewhere distant and send the Alien looking. This requires a successful Stealth roll to throw--if failed the Alien gets an immediate perception roll, minus her SPs generated to see her. If it works, the Alien will (a) Start Looking for her (meaning it gets a roll where every score below a 10 adds to the Target Number) BUT: she can make a Run move at +0 (for a flare or can) or even +2 Stealth for a Noisemaker (it's so loud it covers her running). This is a way to either get to far cover, exit a level, move through a wide open area, etc.
Also note: The Alien will kill other life-forms in the area so if you distract it in the direction of people it wasn't attacking, it'll see them (exactly how THIS works in the game is ... a mystery: it does find them and kill them--but it seems to be "hunting" Ripley--it certainly doesn't find them and kill them as efficiently as it does Ripley!).
I think there would be room for player-generated ideas such as getting a less-than +4 HIDE for laying flat under cover (something you can do in the game). We'd also want to figure out how the motion-sensor works ... some stuff like that.
One note: Why does Amanda Ripley have Stealth L2 14-? Probably because it was a small number of points and she's a space-faring PC whose player knows the value of being sneaky. What about the (hypothetical--but kinda pricey Sneaky Trait?). Well, in this case, the player knows that the game may well involve the character hiding from danger rather than shooting it out and has that trait as more expensive than L3 (which will, in a non-Drama situation ignore negative modifiers--but will help more in a straight-up Stealth roll if they make the 14- roll). Secondly, in Dramas, L3 would be more cost effective (2 CP for +3 to the SPs)--but this gives more (+4).
Obviously you'd want L3 for the Drama-after-Drama-after-Drama situation (where the professionally trained expert Ninja would be actually skilled at bypassing Aliens by stealth) but the trade-off seems worth it.
The GM might well provide things "along the way" on a level that could re-charge the SPs (for example, finding a video-diary 'cut-scene' or reaching a "com-terminal access" (save) point? This would go well towards making the SPs battery worth more.
This framework might not be perfect--but it could be cool. It could be a tense, exciting episode for a stealth-based character.