The Maze of One-Way Doors

Not too long ago, I played in a game which contained a maze of one-way doors. From one side they appeared to be normal doors. However, once the players had walked through them and the door was closed, it simply did not exist on the other side. Whether this is the work of marvelous engineering, or simply magic, it’s not important. The important thing is that once the players walk through a door, they cannot walk back out the way they came. They must move forwards.

I liked the idea, and so decided to give it a go myself. I constructed a maze of moderate size. It was primarily made up of empty 10′ x 10′ rooms, but there were a number of puzzle and challenge rooms to add variety, along with a pretty interesting encounter table. I thought it would be a lot of fun to run through, and to my delight, the players did find it and enter the maze.

The players in this group are very good, though, and they were careful in their approach. The party’s fighter entered alone at first. He opened a new door to look through it, and in doing so caused the door he’d come through to close. He returned to where the door had been, and pounded on the wall to let his companions know they should open the door, which they did.

Having discovered the trick, the party decided to leave one party member in each room they passed. So one party member would stay outside, and the remaining two would enter the first room. Then one of them would remain in the first room, while the last party member went into all of the adjacent rooms, and opened all of the doors in there to look inside those rooms. Using this method, they were able to discover a route from the first room, back to the outside of the maze. Since they knew a way out, and thus no longer needed someone outside the maze, they were able to systematically map a large portion of the maze.

The players were clever, and I approve of clever play. Unfortunately, it wasn’t fun. For them or for me. Essentially all I was doing was reading them a long list of room descriptions within their searchable zone, while they took notes. The encounters were entertaining, but the encounters could have happened anywhere. They would have been improved by placing them outside of the maze, because the maze was boring.

Eventually the players gave up and headed off to a different area of the dungeon. And I’m left to wonder: can a maze of one-way doors be done better, or is it simply never going to be fun if your players are cautious and skilled?

Some thoughts on how it might be improved for more highly skilled players:

  • I had a warning of sorts printed above the door. “To enter is easy. To become lost is easier. To return is failure. To die is worse.” I thought it was cool and thematic, but it’s what put the players on edge in the first place. Without it, they probably all would have entered the first door together. I think, though, that they’d still have landed on the same strategy. Particularly if they ended up on one of the many failed paths which leads back outside of the maze.
  • There’s no reason to assume that a one-way door would allow sound to pass through it. By soundproofing the maze, I could prevent the characters from requesting a door be opened from the other side. Of course, I can’t stop the players sitting at the table together from talking, and telling them they can’t just seems dickish. Plus, the workaround seems obvious: “Open this door 60 seconds after it closes.”
  • I like one-way door mazes because they’re a challenging trap which could conceivably be engineered. But if I’m willing to amp up the magic, I could say that each door is a normal, two-way door so long as there are people on both sides of it. Only when everybody has passed through the door will it become a one-way door. And, so long as any door in the room is a two-way door, none of the other doors in the room exist. (So one can only attempt to move forward once everyone has entered the new room and become trapped in it.)

I’d be curious to hear other’s thoughts on one-way-door mazes.

19 thoughts on “The Maze of One-Way Doors

  1. If you made the doors one-way portals, then players couldn’t leave someone behind to open the door. That’d probably make the puzzle a bit more complicated.

  2. What if the door didn’t disappear behind them. They open it and appear to see the party standing there waiting for them. The characters might even be able to communicate with each other through the illusion. Only very gradually reveal to the players they are lost.

      1. If the the remaining PCs enter the room with the scouting PC, they enter it, no illusion required. If the scouting PC goes to report back to the rest of the party, his illusion only will enter the room. The scouting PC would then be looking through the eyes of the illusion. The party can interact with the illusion as they would the character. It may be that certain actions or lines of questioning could give one or more PCs the ability to disbelieve it.

        1. So, if I understand you correctly, the scouting PC never leaves the room they’re scouting. They just experience an illusion which makes them and their party think they’ve left the room?

  3. What if not every door was one-way, the one-way doors were spaced out, and the maze was heavily populated with scavenger monsters? That way the issue isn’t the one-way doors but the threat of being separated and overwhelmed by smaller threats that would otherwise be dismissed by a full party.
    The doors could also be timer locked like a bank vault. Once the door closes, activating the locking mechanism, it stays locked for a set time (10-60 minutes).

    1. I really like the idea of a locking mechanism. It’s short enough time that the players ought to be able to move through the same room multiple times without issue, but long enough time that they’d feel compelled to do something rather than just wait around.
      I’d like to avoid an over-reliance on monsters in this section of the dungeon. It’s primarily puzzle / social encounter based. However, as a motivating factor, random monsters never fail. A good last resort move if other options don’t pan out.

      1. The locking mechanism would go really well with a time element: flooding dungeon, find the treasure before the sun sets, wounded party member/ally). The doors can be obvious enough that, after the first, the PCs know which doors are which, but the mechanism that closes and seals the door is strong enough to prevent them from being propped open (like the subway doors in New York City).

  4. Hmm. I guess I look at it from the standpoint of what would happen if the party never noticed the gimmick. What are the consequences of this maze if the party doesn’t figure it out?
    Is it possible to end up stuck forever in a room with no exit? For an extremely unobservant party, this would be functionally equivalent to walking through a series of seemingly normal rooms and suddenly triggering a deadly trap with no save. You could argue they deserve it for not being observant enough, I suppose.
    Are there no consequences and eventually you end up in another part of the dungeon? Again, for an extremely unobservant party, assuming there isn’t any spatial/mapping trickery, this would be functionally equivalent to traversing a bunch of rooms and then later when you try to return to town, one door on your way back is suddenly not there.
    So what I’m concerned with is, what is the incentive for wanting to backtrack? What’s the difficulty for the party that forces them to think about how to game these one way doors for a reason?
    I think this could be a good idea in conjunction with a puzzle that ties it together, making the traversal important.
    Maybe something like the classic traversal puzzle. In the entrance room, you pull a lever that resets the maze. Then as you walk through, you can never take a path that would result in entering the same room twice. The party has to get to a certain room, where something about it makes it obvious that they need to visit it last, and they have to pass through every other room on the way there.
    What happens when you get stuck? I don’t know. Maybe they get teleported back to the first room, or maybe they fall through a trap door into a chute (there’s one in every room and they all funnel you to the same dumping ground).
    How about this to make it fun, too: one of the rooms has a huge pit in the middle. A south door has a catwalk to a west door, and a north door has a catwalk to an east door. Because they can never enter this room again, the party has to figure out whether they should enter south and go west or enter north and go east (or the other way around).

    1. First, I think it’s perfectly fine to allow a party to walk into a trap with no save–so long as there are plenty of warnings along the way. So if there WERE a dead end room where they would be trapped forever, it would be fine. So long as it was several rooms deep, giving the party time to realize what kind of area they were in.
      That being said, I didn’t do any such thing. I made sure when designing the maze that every room can, eventually, lead either back to the entrance, or to the exit of the maze. (Though there are a few paths which could place the party in significant peril, but I’d rather not discuss those where my players can read.)
      Your idea of a traversal puzzle is a good one, though its significantly outside the scope of this particular puzzle. Functionally, this area serves as a minor mapping challenge. Players who keep a good map will wander around for a short while, encounter a few interesting things, then come out the other side.
      It has the secondary purpose of being a test of the adventurer’s resolve. Upon entering, there’s a very high probability that they will quickly find their way back out (most roads lead to the start), and then they have a choice to make. Do they enter the maze, seek whatever treasure lies at the end of it, and risk the possibility of cutting off their ability of retreating?

  5. And how about this.
    There’s no solution that allows you to traverse every room exactly once…
    Unless someone stays at the entrance to pull the lever, re-enabling all of the doors and allowing the rest of the party to start from one of the rooms in the middle!

  6. Have you ever played Ico (PS2)? You have to escort a princess through a castle riddled with puzzles and the occasional monster. She cannot fight back and the monsters attempt to kidnap her – but her presence is the only thing that can open certain doors blocking your escape from the castle. She also cannot climb too well, (think normal climbing vs a thief’s climb sheer surfaces), does so slowly, and cannot run as fast, and then only for short distances. So some times you have to leave her behind somewhere while you climb a dangerous cliff to open the gate blocking the way.
    What about portals that kept out certain things/people (elves, magic users, those who have killed with steel)? The party then has to leave someone behind, find the switch for THAT portal, then return or those left behind play catch-up until the next such portal?

    1. I watched my girlfriend play Ico. Its quite the hidden gem on the PS2, one of these days I ought to sit down and really play it for myself.
      This idea would be complicated to implement. I prefer puzzles where the player doesn’t need to track too many different things at once. But if it was crafted carefully, I think this could work. Thanks for the input!

  7. I see a simple solution that was touched on above. One is more mundane and allows some limited backtracking, while the other strictly disallows backtracking.
    1: You cannot open any other doors in a room until all doors are shut.
    2: The ‘doors’ are actually magical, one-way portals that tie two rooms together. The rooms are not physically connected. When a player goes through a door, they look back and see a blank wall. The players on the other side can see and hear him/her through the door, but s/he can’t see them. There is no way back once you enter.
    To mitigate the possibility of having to trek through each and every iteration to find the exit, you can have clues and riddles that point the right way and some rooms may have a special trick/trap that could put them onto another path (with or without their knowledge).

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