In my previous post, I introduced gotcha traps, the first of my two categories of traps. This post reveals my second category.

puzzle traps

While characters must search for gotcha traps, puzzle traps always come with clues that signal their presence. With puzzle traps, the fun comes from either deciphering the clues to locate the trap or from working out a method to evade the trap, or both. The details of these traps matter. Because puzzle traps exist as tests of player ingenuity rather than character skill, the party’s rogue probably lacks any special advantage. Players rarely disable a puzzle trap with a quick check, rather they work out the game-world steps required to circumvent the threat. For more on the sort of game-world problem solving encouraged by puzzle traps, see my post, “Player skill without player frustration.”

Puzzle traps work like other obstacles that demand player ingenuity to bypass, but they bear an extra burden to be fair because of the danger to the characters. If an ordinary obstacle proves inscrutable, the game just slows until the players go another way—or the dungeon master has something come through the sealed door from the other side.

On the other hand, the stronger the warning signs that accompany a trap, the more you can increase the trap’s peril. If the players find a gem surround by a ring of blasted corpses, they will accept a certain lethality. Everyone loves to see a reckless instigator get zapped.

“Gee guys, something about that gem just seems a little off to me.”

To make puzzle traps work in the game, players must see evidence of their presence. Include clues that hint about the traps. Make the clues just subtle enough so the players either feel clever for figuring things or chagrined because they missed all the hints that now seem obvious. The last thing you want is players feeling they’re characters are dying because the DM wants to prove his superior ability to add arbitrary traps that kill characters.

For example, if the players spot a shaft going up with spikes at the top, they will fairly expect a trap that flings them up using, say, a sigil of levitation. But if the shaft is covered by a hidden trapdoor and players only find the smashed helmet of the last guy to crash up, the clue rates as too obscure.

Trap builders seldom advertise their work, but clues can come for other sources:

• Earlier explorers leave signs that a trap has been triggered or bypassed. For example, the characters enter a room with spikes driven into the stone walls at ankle height. When triggered, the bottom of the floor opens to a pit. The spikes gave prior explorers a place to stand.
• Disabled, tripped, or obvious examples of a trap appear earlier in the dungeon, revealing tell-tale signs of similar traps later on. For example, statues of warriors poised with real weapons line a passage. Midway down the passage, a decapitated skeleton reveals the two statues rigged to swing their swords. Later, the party finds a similarly decorated passage, but this time the trap triggers two statues bearing crossbows.
• Maps, rumors, or hints reach the players from earlier expeditions or from other dungeon residents. These sorts of clues can bring social skills underground. Can the players trust a captive to lead them past a trap, or to lead them into one?
• The dungeon’s builders built in puzzles or clues to test intruders’ cunning. For example, the entrance hall of the Tomb of Horrors includes a lengthy clue written into the floor. (Too bad Acererak’s obfuscated, ambiguous clues are almost as likely to send characters to doom as to success. Do avoid anything green though.)
• Current denizens left evidence of the methods they use to bypass a trap. For example, players wade through a partially flooded passage and find a broad plank near a door. Unknown to the players, the door opens onto an unflooded stairway down. Opening the door causes a rush of water to sweep the the players down the stairs. Before opening the door, the dungeon’s inhabitants block the water by setting the plank across the bottom of the door, and then they step over the plank.
• The trap gives signs of arming arming before it triggers. For example, someone steps on a floor tile and hears an audible click. This forces the rest of the party to search for a way to disarm or avoid the trap before the unlucky character raises a foot.

Usually, with puzzle traps, using the clues to decipher the nature of the trap leads to fairly simple countermeasures. Don’t stand there. Don’t touch that. But sometimes evading a trap can present as much of a puzzle as finding it. For example, consider my reverse pit, with the upward shaft and the sigil of levitation. To bypass the trap’s obstacle, players might need to secure someone with a rope to be raised to a passage half way up the shaft.

As I wrote this post, I scoured some classic, trap-filled dungeons looking for examples of the sort of puzzle traps that I recommend. Even though the classics served as my inspiration, I found few examples that suited my principles. Are my standards for trap design overly high? What published adventures contain puzzle traps such as the ones I recommend?

Related: Ars Lundi did a post on traps that reaches some of the same conclusions as I do. In the post, Ben Robbins calls the two categories zap traps and interactive traps. I like his term of “interactive traps” better than my term “puzzle traps.”