Math Games

Deadly Rooms of Death

Ed Pegg Jr., June 16, 2005

According to ratings at, the best puzzle game of all time is Deadly Rooms of Death: Architects' Edition. This puzzle game is beating out such puzzle classics as Doug Beeferman's Cyberbox, Robert Donner's Minesweeper, Hiroyuki Imabayashi's Sokoban, Cliff Johnson's The Fool's Errand, Scott Kim's Heaven & Earth, John Kindley's Laser Tank, Peter Liepa's Boulderdash, Andrew Looney's Icebreaker, James McCombe's Vexed, Alexei Pajitnov's Tetris, and Zillions of Games.

The original DROD -- Deadly Rooms of Death -- is free. The original designers relaunched an improved version of the game in April 2005 -- DROD: Journey to Rooted Hold ($20). After getting various recommendations from my puzzling friends, I decided to check it out.

Figure 1. An initial room in DROD: JtRH (click to enlarge)

As the game starts out, Beethro Budkin, fifth generation dungeon exterminator, is showing his nephew Halph a dungeon. They soon become separated, and Beethro goes to the rescue. DROD doesn't initially feel like a puzzle game -- it has a plot (repeat - it has a plot!) with wonderfully voice-acted characters (over twenty pages of script). The various game mechanics are gradually introduced as a part of the story, so there is no slow down to explain mechanics. Much of the game seems to be about hunting down monsters, a popular genre not often associate with puzzles.

Figure 2. A more puzzling room (click to enlarge)

Soon, Beethro encounters a more difficult room (Figure 2). Each turn, Beethro can move one space, or turn his sword one space. The cockroaches move one space toward Beethro each turn. If any of the giant cockroaches reach Beethro, he's killed. Here's a hard math problem: What is the minimum number of moves needed for Beethro to kill all the cockroaches and leave the room? So far, the record is 63 moves.

Anthony Flack commented thusly: "The puzzles are indeed really good, and the in-game dialogue and character interactions are a perfect example of how effective this can be when it's done well. It really hooks you in. Plus, it's a puzzle game. But it doesn't feel like you're playing a puzzle game. It feels like you're playing Gauntlet." Unlike most games these days, DROD is turn-based, so you don't need good reflexes, just an ability to think. Beethro moves, then the monsters move. Of the many times I've accidentally let Beethro die in the game, 99% of the time I pressed a movement button before thinking (I really need to stop doing that).

Figure 3. Beethro meets the unassailable 39th Slayer. (click to enlarge)

After finding Halph, Beethro starts realizing that something sinister is afoot. A unsettling bureaucrat tries to convince Beethro to leave the dungeon, but he refuses, so she starts the paperwork necessary for a slayer. The 39th Slayer is an unstoppable assassin whom Beethro can only flee from. 39th Slayer has an excellent artificial intelligence, and is creepily voiced by Todd Downing. Although I play computer games of all sorts, no game has gripped me with fear quite the way as 39th Slayer unexpectedly showing up with a deep, gleeful "There you are," before locking the room's only exit. In his Gamer's manifesto, David Wong starts with "Give us A.I. that will actually outsmart us now and then." DROD is one game that delivers.

Figure 4. A difficult maneuvering maze with three cockroaches and a bomb. (click to enlarge)

Some of the puzzles are hard enough that you might be desperate for a hint. I had trouble with the room above. Each of the three roaches must be herded into the central room. If any of them move onto a force arrow, they get stuck. In a way, this is a multistate tilt maze. Conveniently, the DROD site is set up with a well-organized hints forum, giving progressive clues for solving the harder rooms.

DROD's roots began in 1982 with designer Erik Hermansen's "weird fascination with graph paper." (I, too, had a fascination with graph paper.) Erik originally designed DROD on a chessboard in 1991, and finished the first program for it in 1993. By 1997, Webfoot Technologies abandoned support for the game due to lack of sales. In 2000, the game went open source. From there, the many fans of the game started making their own puzzle rooms. Erik hired the best designers among these fans for the current version, Journey to Rooted Hold. Unpopular puzzles were cut, simplified, or eliminated. For instance, there was a large, sprawling maze in the original DROD. Erik: " By popular uh... opposite-of-demand, there is no maze level in Journey to Rooted Hold." Rooms similar to one another were combined or eliminated. Of 40 already-coded game elements, each was carefully evaluated from a pacing perspective, and many were excised.

The careful honing allows a range of new, interesting puzzles to be introduced gradually, as a part of the plot. Their site has multiple pages on the proper way to design a room -- good advice for anyone designing a puzzle, a course, or a homework assignment. Architect Toolkit #2, point 7: "Try to have a progression of difficulty across a level, or across the entire hold. Also consider interspersing difficult rooms with more moderate ones, or somehow pacing your level so you don't traumatise the player. You're an entertainer. The player is not your victim upon whom you are conducting a relentless, merciless campaign of evil experiments." Architect Toolkit #2, point 5: "If possible, try to come up with a broad theme for your levels. Don't stick to it 100%, mix things up a bit, but perhaps give the player a few ideas to latch on to, so they feel like they're getting good at some particular set of skills. Players are then rewarded by their own increase in skill, and therefore self esteem." If I can paraphrase, make sure your students have fun while they're getting smarter.

Surprisingly, the elements that remain pretty much make their own programming language. An example of the flexibility is demonstrated by a user hold, The Palace of Puzzles.

Figure 5. The Palace of Puzzles, by VortexSurfer.

The Palace of Puzzles looks like a normal hold, but each room is carefully built around an excellent puzzle. Many of these puzzles are NP-complete themselves, and thus so is DROD in general. These are 20 superb puzzles in their own right.

Alphametic: WHAT+THE=HELL Military Tactics by Sam Loyd Peg Solitaire James W. Stephens' Kung Fu Packing Crates Minesweeper Path, from the Google US Puzzle Championship Tilt Maze, by Andrea Gilbert
  Bicycle Tour, by Sam Loyd Hiroyuki Imabayashi's Sokoban   Bishop's Tour Red-Green-Yellow Maze by Robert Abbott
  Wolf-Goat-Cabbage puzzle Flashlights and Bridge puzzle Magic Square Tweedledum and Tweedledee logic puzzles by Erich Friedman  
3&5 Gallon bottle puzzle Eight Queens puzzle Knight's Tour Adrian Fisher's Jumping Horse rolling block maze 123 Maze by Hiroshi Yamamoto Closed loop puzzle

This is just one user-designed hold. Many, many other puzzles and holds have been designed by the large community of DROD fans, most of them available free. Thousands of difficult rooms are available, making series of puzzles rivaled only by LaserTank for sheer size. For those that purchase the spiffy new version, a revamped remake of the original King Dugan's Dungeon will soon be released by the developers. For the future the developers plan a sequel, The Rooted City.

After spending several weeks on JtRH, I've embraced it. I've always loved puzzles, and these are some of the best I've seen. I can't wait to see what comes next in the plot (18 levels, and 39th Slayer is still after me). The game is huge, clever, well paced, and entertaining. I agree with the high praise that DROD: Journey to Rooted Hold has gotten so far -- this is the best puzzle game of all time.


Erik Hermansen,,

Erik Hermansen,,

Home of the Underdogs, "DROD: Journey to Rooted Hold,"

Wikipedia, "Deadly Rooms of Death,"

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Ed Pegg Jr. is the webmaster for He works at Wolfram Research, Inc. as an associate editor of MathWorld, and as administrator of the Mathematica Information Center.