Take a look at Break & Enter by Emerald Press. I have a copy and it provides an excellent framework for stealth encounters complete with stealth kills and ways the entire party can participate. (Link to driveThruPress)
It offers a way of calculating "unaware HP" that only enemies not aware of the players' presences have, and adjudicating attacks against them. It's certainly worth trying if you find your players wanting to do quite a lot of sneaking, as the default rules do not support that kind of play.
Without going into detail about the excellent stealth mechanics, guards going on their rounds and so on, we have selected excerpts:
To understand the function of a stealth encounter, we must
first explore its need. All heroes find themselves between
a rock and hard place at some point in their travels.
Your dailies are used up, most of you have expended your
second wind, and you’ve wound up knee deep in enemy
territory. Taking an extended rest is not possible until you
find a haven somewhere within the dragon’s lair away from
the uncounted demon minions guarding that immense
treasure and patrolling the winding caverns. Up ahead, a pair
of drakes feed on their latest catch. Their backs are turned to
you, their snouts engorging on the innards of a poor villager.
According to the map, you’re mere feet away from the
guardhouse and the door just behind those beasts is the only
means to access the inner sanctum of the lair, but your party
is weak from your previous efforts. You need to take out those
drakes quickly and quietly.
Cue the stealth encounter.
Stealth encounters allow the GM to replace an existing
combat sequence with subterfuge and surprise without
altering the build and composition of the player charac-
ters. By sneaking up on the unsuspecting drakes in the
example above, the PCs can eliminate them quickly without
any unwanted attention from other targets nearby. They
use skill checks (just as they would in a skill challenge) to
create combat results (as with a combat encounter). More
importantly, running a stealth encounter allows the GM
the opportunity to continue large portions of an adventure
with few modifications until the heroes find themselves in
a favorable situation or it is no longer feasible to creep and
skulk. Once the PCs get past the drakes in the paragraph
above, they can continue sneaking through the lair until they
have been spotted and an alarm sounds or they reach the
dragon himself and engage in open combat.
...
Unaware HP is a mob's Constitution modifier (minimum 1) with more if they're large, and wisdom modifier if they're elite or solo. Standard creating a mob calculations for everything else. (page 24-25)
Looking at how this plays out, the emphasis is on quiet, silent, attacks... rather than big flashy attacks that make noise, have arrows passing through visual range, or have showy magic. Because an elite or solo can be dropped by any character in a round, a scene's tension is not in 5 rounds of combat, but a slow build over many rounds of a successful sneak to get to that point. When considered over average numbers of rolls, the amount of time a character spends getting in position, cleaning up after the body, and the number of stealth checks necessary more than makes up for the quite neat consequence of dropping the solo in one hit if everything goes according to plan.
I set a limited numbers of must, might and should rules for character creation. Those generally look like:
- Your character must agree to do X — plot of the game. For example, work for Black Mesa, help NPC X, need work because of repayment on space ship, yadda, yadda…
- Your character must have Y — linked to theme of the game. For example, be a known hero, have space ship crew experience; be a wizard of the White Council, yadda, yadda…
- Your character must be willing to work with others. No loners.
- Your character should speak language X — so all your characters can understand each other.
- Another character may be your friend, ex-lover, contact or/and acquaintance.
- Another character may have worked with yours in the past.
The reason I do this is because I am building a story in which the protagonists must, should, and might have those things. Otherwise, they are not protagonists and thus have no place as a PC for this game.
Best Answer
I keep the following principles in mind.
Puzzles are interesting in tabletops. Unlike ARGs and Pervasives, where the puzzle is often a key element of the game (and thus real) the players don’t actually have to solve the puzzle (though they often should put the pieces together), they just have play through it. Unlike movies and tv we don’t need cool visual moments, we need cool interactions. So we’re closest to books, and if you want to really do well in this read some great golden age mysteries, for example.
What I do is usually develop a set of interlocking clues that lead from the central, crucial clue. Because I’m a big fan of suspense I also give interrelated stuff that is secondary but can help put the picture together. And because I’m a visual person I do this with a visual aid.
I start at the end. In this case there is some horrible prophecy that will result in horrible things happening. Not the least the death of someone important.
Now we go to the beginning. Art galleries are fun. So we’ll have a scene at some opening of a painter, probably one I’d develop. There will be some art critic and a socialite and someone else to deal with. Probably my shadowy occult leader or an underling. During this scene someone in the group (the art historian type) will get a clue that is buried in the painting.
Our socialite/heiress will be kidnapped. There will be some clue that will force the players to the graveyard if they weren’t already on their way. Maybe they stop the kidnapping. Want to be prepared for that.
At the graveyard the players find Aramaic writing. Maybe they can read it, maybe they can’t. If this is a oneshot they wouldn’t be able to because that drives them to our professor of Aramic, which is another cool scene.
Somewhere along the way the cultists try to kill them. I'd keep this moment for when things slow down.
By this point we have a central clue trail (painting to graveyard to deciphering Aramaic) that tells the players what is going on. The heiress kidnapping and the attempts on their lives gives them supporting clues that allow them to show up and stop the cultists.