Want to know how to scare the pants of your players and create suspenseful adventures? Well, you've come to the right place!...so long as you don't mind a little humor along the way.
Pants Piddling and Mindless Horror 101
Warning: This Post Contains Dead People
Warning: This Post Contains Dead People
1. Fear and Danger: The first key to generating a suspenseful adventure is an element of danger. This will generate the required fear and suspense you're looking for. The element of danger must be hidden and worthy of fear. I'd recommend keeping the antagonists of the adventure hidden or at least only spotted in the shadows. Allow the player's own minds to dream up all sorts of horrors. Have strange dead bodies lie around, people die in weird ways, and odd noises and findings throughout the adventure. Feel free to ham it up and exaggerate the shadow of the crazed, murderous beast. It may turn out to be a small weasel, but as long as the element of fear is intact, you're doing your job properly. Most players will scare themselves silly if you give them the opportunity and lay the seeds of doubt.
2. Use Foreshadowing: Just because the players can't know exactly who the bad guy is or what exactly he's doing doesn't mean you can't drop hints. Some of these 'hints' might even be way off base. Allow the players to make outrageous assumptions like they're facing hundreds of invincible, invisible undead or the enemy of the adventure has access to horrible 9th level spells that kill without a saving throw. Allow the piles of odd deaths, clues, and strange occurrences to point to unavoidable conclusions which should scare your players out of their minds. However, not all of these unavoidable conclusions are accurate. The key to suspense is not knowing what will happen next and that's something an RPG excels at. In a movie, the audience wonders if the heroine will spot the zombie hiding in the shower. In an RPG the players should be wondering, "What the heck's in that shower?!" even though it might be nothing or maybe the zombie is hiding in the toilet.
3. Mood and Phobias: Use classic forms of fear building such as the following: claustrophobic places, dead things, mysteries, darkness, beasts, strange or inexplicable noises and occurrences, slime, high places, raving lunatics, and so forth. A simple thing you can do is ask the players what scares them and then about a year later remember it and work it into your suspense stories. The trick is to do this without seeming cheesy. Another good idea is to remember what scared you most as a kid and try to get the 'feel' of that into your adventure. Chances are if something scares you, it'll generate suspense in the adventure itself. Be sure to establish the mood. If the players have no clue what you're doing, they might come into the adventure with the attitude of, well, adventurers. Heroes tend to take most things without being fazed. Let the players know this will be a deadly mystery and suspense adventure. They might not be scared out of their minds, but they'll at least know what you're aiming for and won't complain so much when a psychopath starts ripping their favorite character's head off.
4. The Unknown: One of the best tools in your suspense arsenal is the fear of the unknown. Never be straightforward in your answers to player's questions. Don't say, "There's a dragon in the room." Say something like, "You see a massive fanged beast with talons dripping coming toward you. You know you're in inch from death." Don't interpret clues or occurrences for the players, or if you do, make up the worst thing it could be (even if it's not). When their swords fail to hurt the gargoyle don't say, "It appears to be immune to non-magic weapons." Say, "The being of stone laughs in the face of your blows. It appears to be utterly invincible, moves with the speed of the wind, and wants to rip your legs off."
5. Red Shirts: Go Star Trek. Be sure to include a lot of red shirts who can mysteriously disappear or die. Sometimes someone going missing is more frightening than someone dying. If you cast shades of gray on the characters helping the group, the players are bound to be scared out of their minds by everything, everyone, and any small noises in the night. If you're doing your job properly, that's probably a wise thing. Consider a guy sharpening his knife in the middle of the night. He chuckles malevolently, disappears for a time, and then returns without the knife. One of the players sees this, but when asked about the knife the guys says, "What knife?" Maybe he just lost it in the woods, but with all kinds of crazy weirdness going on this should drive the players nuts.
6. Don't try to Scare the Players: This may sound counter to what I was arguing earlier, but really it's not. Never set out to scare the players. It'll never work; they'll only laugh. Never say, "Oh, this is such a scary adventure with so much suspense you'll all be biting your nails and piddling your pants." It just doesn't work that way. Everyone would love to scare the daylights out of their players on occasion but, literally, it doesn't work that way. If you run a good suspense adventure, and keep up the work they'll appreciate it and they'll still enjoy the game. You might not scare the daylights out of people, but if you do your job right there will be just enough doubt in their minds to cause the creeping tendrils of fear and suspense to invade.
7. Don't Answer all Questions: Even at the end of the adventure, don't reveal everything. Have another dead body turn up after the villain was already captured. What's going on? That's the whole key to suspense adventures. Some should end like the old X-files TV series: with a shred of doubt.
8. Employ Killer Descriptions: One of the best ways to establish suspense is to actively create it. The players take absolutely all their cues about the game world from your descriptions. If you describe something as the fiercest, ugliest, most horrible, and most terrible area ever, and the fact that if they enter they'll probably die, you can bet your dollar the players will just turn around and walk away. Once upon a time I described something to be so fierce and terrible the players just ran over the mountains and never went there. Be sure to include a very good motivation for the players to go somewhere obviously dangerous and of insane suspense value. Otherwise they'll more than likely just run away. For your fearsome description to have any weight, the area must actually be seriously dangerous. Don't overuse your fearsome descriptions either, or there will be problems. I try to include only one suspense adventure for about every 5-10 normal ones. If you go for suspense all the time the players will get used to it and it'll lose that edge you're looking for.
9. Build up Suspense: In literary terms, there is an arc to all stories. The villain is fought at the end, the identity of the killer is finally revealed, the little girl survives the alien attack with the cat. In a game, you can't say for certain the players won't kill the villain the first time he shows up. Therefore, it may be prudent to have him not show up for a while. To build suspense you must start out with small occurrences and strange clues. As the players explore the clues they should find more and more out about the horror of everything. Finally, toward the very end of the scenario, the villain(s) should actually start showing up and taking people down. Have the toughest, wisest, most invincible NPCs die first. If the players have any sense, this should scare them. Let the villain do unreasonable things like kill 15 people in 12 seconds even though they're all hundreds of feet away from each other. Make sure one of the NPCs has the great idea to 'split up' and search around. Separating party members with traps, darkness, or whatever is also a good strategy. In a group, the party is at its strongest and most confident. If you injure the group, split it up, and have their keys to survival thwarted like torches blown out, weapons dropped, equipment destroyed or whatever; you make them sweat. Consider if the party mage was to fall down a pit, lose his magic from a trap, swamp water puts out his torch and ruins his equipment, and then he gets lost and hears growls on all sides. Don't overdo it either, or the players will just think you're out to get them. Don't take it easy on them, or they'll just laugh. There's a balance to it, as in everything. Give them plenty of opportunities to foul up their situation and cause themselves risk and danger of the unknown sort. If you do that, they're bound to give you just the opportunities you need to make them sweat.
10. The Evil GM Chuckle: Sometimes just chuckling malevolently and rolling a lot of dice will do the trick. So long as you don't abuse this, this could be one of your finest strategies for generating suspense. For example: "Oh, so you guys are yelling? Here, let me roll 20d6 for random monsters. Oops, this doesn't look good...Ha ha ha!"
...Yet More GM Advice