I find secret doors to be an overused obstacle. Just how many does a single dungeon level need?
My problem with secret doors is that they are a potential show stopper that even with good play from your players, the dice can decide the door is never found. What lies behind? For all intents and purposes it never existed if the dice decide it was never found.
Concealed doors? Now THAT is something I can get behind. Look behind that armoire. Why are there curtains on this wall? What's under this rug? Good play will reveal with concealed doors what dice may otherwise steal with secret doors.
I think this reflects a poor understanding of the various purposes that secret doors should serve. They should never be a “show stopper,” and if you are not designing boring, linear dungeons that generally should not be an issue. To state the obvious, however, secret doors should not be placed in a fashion that could halt the party’s forward progress in the dungeon.
So what should secret doors be used for? Among other things:
- to segregate a sublevel that somehow differs from the present level;
- to secure significant treasure from casual discovery;
- to conceal a useful additional entrance or exit (e.g., out of the dungeon, to a much deeper level);
- to serve as a hidey-hole for opponents to lay in wait for or seek refuge from the party;
- to hide a route that allows quick or safe passage past an obstacle or hazard; or
- to seal off an especially dangerous foe so that the party does not merely stumble across it.
Nor should secret doors be discoverable by random dice rolls alone. Players should be able to locate secret doors—or at least increase their chances of doing so—through good play. For example:
- intuition as to where searching might prove fruitful based on room or corridor shape or structure;
- careful mapping that reveals curious empty spaces in the level; or
- examination that turns up telltale clues, like footprints that lead up to a blank wall, seams in the masonry that outline a portal, or an unexplained draft that causes torches to flutter.
As for the concern that areas lying behind secret doors might go undiscovered . . . well, this is a game of exploration. It is not a foregone conclusion that the party will unearth all of the underworld’s secrets. There’s no sense of the unknown or adventure in a dungeon that lays bare its mysteries to everyone who stumbles through the front door.