Book Review: The Dozen Dooms

The Dozen Dooms cover: "Swamp
Dragon"by Bob Greyvenstein. C 2020
Bob Greyvenstein, Grim Publishing

Book Review: The Dozen Dooms 

Author: Baldrage 
Publisher: self-published
Marketplace: DrivethruRPG
Engine: OSR Compatible (B/X) 

First off, I want to say two things: Curse you, Baldradge, for beating me to such an awesome book idea! And curse you, Professor Dungeon Master, for being so damn good! 

The Dozens Dooms is a book rule hacks and modifications to apply to B/X Dungeons & Dragons or its clones to create a faster, more flexible, and in some cases, more granular TTRPG experience.

While it is not a retroclone unto itself, it is designed so that if you applied all of the rules in The Dozen Dooms at once to something like OSE or Labyrinth Lord, you'd have a unique and cohesive play experience that would definitely it's own role playing game. 

However, all but one section of The Dozen Dooms is presented modularly and always in such a way that it can be applied to an OSR game without relying on any of the other rules in the book. Where he rules do work well together, The Dozen Dooms has notes on how to use them in tandem.

The Dozen Dooms as a set of rules most of their inspiration from Dan "Professor Dungeon Master" DeFazio and his channel Dungeoncraft, which is one of my favourite YouTube channels. Is dedicated to a mix of designing minis and terrain, and modifying Dungeons & Dragons, both 5th edition and earlier editions to play much more smoothly, and have a more gothic, grimdark feel.

I will not be able to go into every alternate rule or hack here. there's simply too much in this book to give that specific a review. Instead, I will pick out the standouts, and make some honourable mentions aside.

Things I loved

Scalable Target Number System

Professor Dungeon Master and Hankerin Ferinale, the two maestros of OSR rule hacking on YouTube both recommend setting a single roll-over Target Number for all of the most significant parts of an encounter. Professor Dungeon Master, makes a recommendation that Target be based on the desired difficulty with some ideas on how this can work with the increasingly high bonuses that D&D characters tend to have as they level up (the "scalability" problem). Hankerin Ferinale built his entire Index Card RPG Core game on the idea of a single fixed Target number per encounter, but dealt with Dungeons & Dragons scalability issues by simply removing levels from the game altogether.

The Dozen Dooms offers a system for setting a universal encounter Target Number based on the difference between the average party level of the group and the hit dice of a monster, with some suggestions on how to fine-tune. This gives those of us who need more crunch a clearly delineated mathematical process to arrive at what one hopes is a fair Target Number. All without feeling arbitrary or removing the concept of levels from D&D. This tackles scalability quite beautifully.

The Dozen Dooms combines this with advantage disadvantage to remove any large mathematical bonuses for penalties to d20 rolls.

The Dozen Dooms Countdown

The Dozen Dooms has a countdown system to generate a sense of urgency in the PCs. The mechanic is fairly straightforward, at the beginning of each session a randomized secret counter is established on a d12. Every time the characters fail spectacularly on a roll where they have been given a high chance to succeed, such as advantage using a re-roll, having special luck abilities, for expending a Hero point. These spectacular failures increment the Doom Counter down. If it reaches zero, the players roll a d12 on the table of misfortunes and disasters that might afflict the party.

The tables here are well-thought-out, giving a variety of possible complications that will make sure the players try not roll needlessly, and discourage them from abusing mechanics that grant them additional advantages.

Extremely helpfully, the appendix has different Doom tables for different environments and play levels. For example it has both high and low level tables for swamps, tombs, dungeons, mountains, etc.

Alternative Experience and Levelling System

I often steal the levelling and experience system from Dungeon Crawl Classics RPGs for use in my OSR games. I find it is a light, flexible, and scalable to handle character growth. The Dozen Dooms, however, offers one that I like so much that I immediately integrated it into my Low Fantasy Gaming campaign. The system is very simple, every level is gained when 10 experience points are awarded, but experience is awarded by way of mission objectives for significance obstacles, rather than specific encounters.

Because the system doesn't focus on the XP gained by monsters, nor does it focus itself on relative lenel, but rather on how player characters handle obstacles in an adventure that is presumably adjusted by the DM for them, it also reduces the issue of scalability.

Numerated Alignment System

I first became aware of this concept on Professor Dungeon Master's YouTube channel. The idea of measuring a one-axis alignment system not by simply determining whether character is Chaotic or Lawful, but rather, assigning them a number that represents how Chaotic or Lawful they have behaved, which shifts as a PC makes choices.

The number can be put to a number of possible mechanical uses. This idea has been explored in a few places online, and I have seen some very clever applications of it. While the version in The Dozen Dooms is only an introductory version, and doesn't use numerated alignment very much mechanically, it is a good starting point.

I have used one myself as part of my own Pacts & Blades-inspired alternative magic system. 

Non-Vancian Magic System

Rather than using spell books and Vancian spell memorization, it The Dozen Dooms offers an alternate system in which characters may cast any spell in the repertoire by making a spell roll, and expending a pool of spell points. At low levels, this makes wizard's (Magic-Users) a little more powerful, but brings them in line with there vanilla BX counterparts by fifth level.

Failed spell rolls not only cost spell points, but come with a risk of Miscasting, with wild effects, and on a particularly abysmal roll, Corruption (mutation) or Insanity are also possible for wizards. Instead of corruption, Elves become more cruel and psychologically alien if they fell dramatically on a spell check. If you are using the numerated alignment system, they slide towards Chaos. Crusaders (Clerics,) on the other hand, may need to perform an atonement after severely failing to cast magic to prove their faith to their deity.

Wizards are permitted to learn as many spells as they can discover, and have a much larger reservoir of spell points. Elves and clerics get fewer spells, and their magic does less damage, but Crusaders have access to whatever the day if he chooses to grant them, and elves may instantly learn any spell they see cast to a limit based on their level and charisma.

Overall, the system is simpler, it feels like a good compromise between magic with an infinite number of spell of rolls like those found in Dungeon World or Dungeon Crawl Classics RPG, on the one hand, and the hyper-restrictive magic system in vanilla B/X. It both opens up spellcasters to use their magic regularly even at low levels, and adds limits that require spell-casting to be done judiciously.

Insanity Mechanics

The insanity mechanics are one of the main reasons that this game has an Adult Content warning. Insanity mechanics are pretty standard fare, and have been since Call of Cthulhu first hit the shelves. These days they are handled a little better than "Your character turns evil and becomes an NPC controlled by the DM." But it can be a thorny issue. Baldrage makes a point of warning the readers and emphasizing the point that this is not meant to belittle real sufferers of mental illness.

The Dozen Dooms then goes into an insanity mechanic that makes a great deal of sense, we're in the players accrue stress and trauma in the form of insanity points which can be cured with downtime, prayer, or drugs and alcohol or even just being around a bard. Player Characters who accrue a critical mass of insanity points without bleeding some off suffer a temporary malady that is randomly generated. The maladies themselves are pretty typical of an insanity table for a dungeons and dragons derived game, and I might consider replacing it with the madness table from Low Fantasy Gaming. The insanity points and how to manage them, on the other hand, is quite brilliant.

Classes, Skills, and Paths (the good)

The Dozen Dooms presents alternative versions of the seven core B/X Dungeons & Dragons classes. The warrior, the crusader, the wizard, the thief, the dwarf, the elf, and the halfling. These variants are designed to work with several of the existing alternative rules. They list no attack bonus, nor do they have an experience point per level listing, nor saving throws. These things are all now handled using the fixed Target Number system. it lists the specific way that the spell-casting classes use the alternate magic system.

These alternate class listings indicates when the class gains a bonus to damage to a chosen primary mode of attack (ranged, melee, and magic), and the point where they gain skills.

The skills system is not like a modern TTRPG list of things your character knows how to do and may roll for. Instead, it is a set of perks that a character might take every two or three levels (depending on their base class) that give them complementary abilities. A warrior's list of available skills includes abilities to allow them to perform field surgery, do repairs on damaged equipment, intimidate through displays of skill, or trip or disarm opponents with their attacks. The skill system allows a character to gain some customized tricks without changing the fundamental structure of the game as a structured skill system, does.

Paths are a more specialized version of a given class. At fourth level, or higher if the player couldn't meet the requirements right away, they can grab a set of alternate features that improve at level 6 9 and 12. 

The alternate classes are so detailed, especially through the paths that they take up roughly half of the volume of the book. While they are the one section of the book that is designed to use several of the other rules, rather than being directly applicable to an OSR game, there's plenty that could be mined, such as alternate spell lists, and used without taking on The Dozen Dooms' other mechanics. Or, because these are class analogues, they could be overlaid on top of OSR classes.

 I certainly appreciate that they give a level of customizability without needing a system as complex as kits, prestige classes, or sub-classes are. And they really are a lot simpler than any of those. (Although, if I were to compare it to any, I would say it was closely resembles AD&D2e's kit system.)

The Sorcerer Path

One of the wizard paths available to player characters is that Sorcerer. The Wizard PC taking this path gives up casting spells, and instead can describe any effect they would like to create, with an effective spell level and spell point cost determined by the Dungeon Master. I like the creativity of this setup; it lets you leave the Vancian system behind a little further behind if you and the DM are both comfortable doing so. And it opens the door wide open for creativity. The drawbacks are that the character suffers magical miscasts far more often, and has disadvantage when saving against corruption. This turns your incredibly free-form magician into a ticking time bomb, which I love. The magic for this path feels at once more free and more dangerous.

Treatment of elves

In traditional B/X derived OSR games, elves are a racial class that mixes combat ability and spell-casting. it is always being uncomfortable marriage, as the elf has to wear armor and eschew spell casting to make the most of their combat abilities, or stay back out of combat and strip off their armor use their magic.

Baldrage's take on it is different: Elves can do both, but they do not cast spells as well as Wizards, nor do they fight as well as fighters. What differentiates them is that they can use their spell points for things other than casting spells. Elves can learn ways to boost their combat abilities by using their magical resources up while still being armored.

As an elf levels up and gains access to paths they can choose to lose some of their martial prowess to become more like a Wizard, while retaining some combat ability. Or they can choose one of several paths that take away spellcasting altogether and let them further enhance their combat abilities with their spell points to dramatic effect. The paths also include a Ranger path that gives elves wilderness survival skills such as tracking.

Half elves and half orcs

In many ways, The Dozen Dooms is a tool for adding more complexity to B/X Dungeons & Dragons without sacrificing the inherent openness of Basic and Expert sets. Sometimes it does this by taking concepts from later editions of the game and stripping them back to something that would work in B/X.

One of those offerings is that Half-Elf and Half-Orc are presented as racial classes in the style of B/X D&D. The Half-Elf is a roguish character class that offer skills based on social manipulation, while the Half-Orc is a fighter class that deals more damage, rather than taking more damage making them a complement to dwarves. Some of the most noteworthy archetypes of Half-Orcs and Half-Elves are offered as class paths you can take as you level up.

The Half-Elf offers both and ability set similar to a Ranger, and the only Bard analog offered in The Dozen Dooms. The bard itself is not played as a jack of all trades, but rather as a group morale booster, who heals Insanity points, enhances healing, and gives PCs boosts by using spell points that  otherwise cannot actually be used for spells. These Bards do not add social Skill mechanics beyond the usual B/X fare; instead they have the ability to affect a narrow range of targets with a charm effect using performances, enhance party XP gain by making them famous through ballads, and earn room and board or a little gold by performing. This allows bards to exist in game without opening the social skill proficiency can of worms.

Fellowship points

Building upon the idea of the adventuring party as a fine-tuned machine that comes to respect and understand each other as they adventure, The Dozen Dooms offers a fellowship point mechanic. Team building such as making a party contract coming up with a name for their company or establishing a business together all can build fellowship points. As does completing adventures together. They do not replenish, they can only be earned. And they are in short supply. When they are used, they grant considerable advantages to the whole party for one round as they work together as a well-oiled unit. But, of course, using them also opens the party up to incrementing the Doom counter.

Honorable Mentions

Among the other things you can find in The Dozen Dooms are mechanics for replacing a fixed Target Number for attack rolls and turning armor into a form of damage reduction, simplified training rules, and rules for restricting magic items with harmful magical radiation that endangers PCs that carry too many. Many of these rules have means of tweaking them to be more heroic or more grim dark in the notes. It also does justice to a number of common OSR rules s such as rules for hero points that can be used to buy advantage as a reward for role-playing well, slot encumbrance, and lasting injuries as an alternative to instant death at 0hp. Most are simply written and easy to use. It also has a neatly-written explanation of the simultaneous Initiative system made famous by Professor Dungeon Master. One of the Appendices offers a guide to making papercraft minis that is quite helpful. 

Art and Feel

I have the deluxe hardcover version of The Dozen Dooms, which is not yet available for purchase. And it is a book that I like to look at. In fact, it has been pretty enough to cause some chaos at home.

The moment I got this book in the mail, my wife, who has been playing Dungeons & Dragons for around 23 years, immediately snagged it and looked through it before I could get my hands on it. And the first time I put it down, my oldest son snuck away with it to look at it, too. The cover, the page design, the artwork, and some of the appendices are so appealing in their visual style that both the veteran and the new gamer in my household couldn't even let me look at it to give it a proper review for over a day. And, this is the first OSR book that I have bought and my wife has looked over, and asked me what I'll be using from it after she leafed through it. That's high praise, indeed!

Credit Where It's Due

These rules come from a lot of places, and it can be hard to know where they all come from originally. Where he is using rules from the community, The Dozen Dooms gives credit in the introduction, footnotes, and appendices. I appreciate this immensely. 

Update: Pricing

After a short chat with Baldrage, I felt like making a note on something that I missed. He is offering the book at a very low price point, with the PDF at $1.25, and the upcoming print versions at just above cost. This book will be very affordable. 

Growth Points

I'm going to preface this section with a paraphrase from Ernest Hemingway: 'A critic is someone who stands on a hill and watches a battle below, then afterwards to send to shoot the survivors.'

I'm right now trying to produce a lot of content as an Army of One. A lot of these criticisms come down to the fact that Baldrage is, too. I think it is very wise and very noteworthy that he has marked this as the first edition of his ruleset, because I'd imagine with a little support and a little cash, and once he has a feel for what the audience is going to respond to, I have no doubt either a second edition or an expansion will be in the offing that will be spectacular.

Layout

The Dozen Dooms has a lot of visual appeal. It has elegant borders, a parchment tone background, lots of art, diagrams, and elegantly done charts. I cannot complain about how it looks, especially not at first blush. It also has some very smart choices, like a super-light summary of the rules in the book as an appendix in the back. That appendix is well-written enough that if you have read the rules once or twice, the summaries in the back are all you would ever need to check again. The back cover includes the tables you're most likely to refer to if you are using the combat miscue and Doom Counter rules.

However, for those really useful embellishments, there is also a frustrating amount of empty space. The entire book is in large font across single lines. Baldrage has worked very hard not to leave unfortunate turns in his book, but it has led to massive amounts of empty space. 

With a slightly smaller font, smaller margins at the edges of the page, and a little help from someone who has some experience laying out a role-playing game manuals, the book could probably be significantly more compact. That is to say, I would wager with only a little tweaking you could easily chop 17 pages off. With a serious push the book could probably be up to 24 pages shorter.

The most noteworthy issue is in the class chapter. Each class begins with a page with a single two-to-four line quote. However, with one exception, the next two pages with that begin to describe the character class have lots of empty space. The same quotes could have been placed under the page heading have the book and saved nine pages there alone.

Another Layout issue is that several images have been resized in a way that has brought out the worst in digital anti-aliasing, leaving slight pixilation and blurring that mars well-chosen art. It is even noticeable in the title font on the front cover.

This is, of course a gripe which has almost no bearing on the PDF, but as the book is so beautifully done, I can imagine that the deluxe hardcopy I have could be popular; and keeping the printing cost, and cost to the buyer down, will help get it into as many hands as possible.

Editing

This is another one of those "Army of One" problems. There are several places where there are artefacts left over from previous drafts, chunks of copy/pasted text left in the wrong place, and muddled sentences that clearly were edited several times without re-scanning. They are not abysmal, but one more read-through could tighten this book up elegantly.

Classes, Skills and Paths (the Bad)

With over half the books dedicated to handling the character skills and paths concept, I think it is worth looking at both the good and the bad. And it is fair to say that I have a few complaints here.

My biggest complaint is the sheer volume. Each of the seven classes has at least four path options, and most have considerably more. The wizards top the list, having a total of eight paths, most of which come with their own spell list, and a handful of unique spells for the class. Is it almost stunning volume of choice, and in some places doubles up or duplicates effort. For example, the elf has paths that allow you to use your spell points to vastly enhance your combat with a magic sword, your bare hands, or a bow and arrow, and the ranger also has the ability to enhance their archery with their spell points on top of having wilderness survival skills. Add in a pure magic option, and the Elf is glutted with choice. Including two ways to magic up ranged combat, and two to magic up melee.

The Half-Orc has a scrounger path that is interesting in that is simply a character who is good at finding extra treasure and making bargains. He grants a bonus to treasure at the end of each adventure, reduces item costs, and is god at foraging for food and water. It's an interesting concept, but it pushes the edges of bounded player agency by adding a bonus to treasure. At the end of the day, I find it a fairly underdeveloped option. It doesn't add much to the game aside from a small boost to treasure and a savings in coin. As written, it feels like padding the Half-Orc because it didn't have enough options for the author's satisfaction. I might have like to have seen something like an orc shaman option instead.

Much like the prestige classes of Dungeons & Dragons 3e, some of the more dramatic path options require that the character have accomplished certain tasks. The berserker fighter the dwarven wrathwild, and the half-orc ragetusk all must have killed at least 10 people in a fury. The battle wizard must have gone an entire adventure without casting spells, preferring to use weapns and magic items. The dwarven runesmith must have repaired at least 10 items during the campaign, as a few examples.

On some levels I really appreciate this, because it means that players who have done something difficult or impressive can gain a reward for their character in the form of special abilities rather than treasure or mere experience points. On the other hand, I can see this having a significant effect on how campaigns are planned, and pressure being placed on the DM. For example, let's imagine that a player character sees the dwarven grudgebearer path and wants to play it. (I wouldn't blame them, it's a character class can stun intelligent enemies with streams of curses and invective.) The player might feel compelled push the party towards picking a fight with a particular enemy of the dwarves, whether it is relevant to the goals the other party members or not. Or, the DM might feel pressure to include an encounter with his clans enemies in order to enable the player to take the Path. using some of these classes will require a significant amount of communication between DM and players.

The Skill system itself is a little self-defeating; The Dozen Dooms sets out to offer AD&D levels of sophistication while preserving B/X openness. Once you add a set of Skills, however, you restrain what other players may do. The Tactician skill, for example, allows players to trip and disarm foes during combat, If you include it, it must follow that players without this Skill cannot trip or disarm opponents, r may only do so with a severe penalty, This serves to throttle player creativity.

Halflings

Baldrage comes out and says that in his version of B/X Dungeons & Dragons halfling PCs are the equivalent of a hard mode, and I think that's a fair assessment. They start with no appreciable class abilities, even the ones given to them to hide outdoors in the original B/X D&D. Instead, they rely on the skill system to let them purchase thief abilities such as hide and move silently or pickpocket and find traps bundled in a skill. Or, alternatively, they might take skills that grant abilities built on granting them halfling luck for some benefits from there fearless curiosity. The Halfling paths are key to making a halfling character feel more skillful and valuable to the party. And these revolve around abilities like stealth or luck in an exaggerated manner. Halflings need to start with something unique to make them worthwhile. I would rather see Halflings that have at least some advantage or unique ability at the start to UT them on par with other classes. 

Non-Portable Half-Orcs and Half-Elves

My major gripe with having semi-humans expressed as classes is that it is not done the way that is immediately compatible with other BX material because it is hinged on the skills and path system that The Dozen Dooms puts forward. You could easily tweak an OSE Fighter to get the Skills and paths of the Dozen Dooms Warrior class without much difficulty. But there is not Half-Elf class in Core OSE to fall back on. I would have liked a chart with things like ThAC0 and XP progressions if we wanted to use these two classes in a more vanilla B/X-derived system.

Notes on the Mature Content Rating

Because I'm one of the first two people to review this book, I have been asked about why it has a mature rating including by Hankerin Ferinale himself. As far as I can tell there are five reasons why I might consider giving this book a mature rating.

• The insanity rules are the first reason. They are very bleak, and include compulsive self-harm as a possible outcome of characters being driven mad by their experiences.
• Second is the permanent injury table, which can be somewhat bleak, and includes loss of limbs, sensory organs, or possible brain injury as options.
• The Doom tables themselves include possession, animals going berserk, and murderous betrayal by NPCs. I could see why that might be uncomfortable.
• The 3rd is the witch and warlock path for wizards. This is modeled more on the Satanic villains depicted in the Malleus Maleficarum then a fantasy character. It includes the character being granted a succubus consort and numerous spells that summon flesh eating spirits, and other particularly grim magics.
• Fourthly, in the description of Half-Orcs, it flat-out says that they are usually product of rape. Everyone knows that this is the default in every D&D setting except Eberron, but since third edition, it has not been considered cricket to say so. The topic of sexual assault in role-playing games is very uncomfortable in the discourse right now.
• Finally there's the matter that they have elves are obliquely sexualized, mentioning that many are outcasts, criminals, or sex workers. It also states that the elves themselves shun-half elves because they consider them to be the product of something akin to bestiality. That statement offers just enough of an uncomfortable reference, that I understand why ne might want to keep it out of the hands of curious children,

Personally, I don't see anything here that is out of the ordinary for OSR fare. Insanity tables, mutilations, mutations, oblique references to sexuality, and fantasized interrogations of bigotry are not anything new, revolutionary, or even particularly remarkable. I doubt you would see warrant adult content warning on a Lovecraftian horror system. And let's be honest, the random harlot table in AD&D first edition is more risqué than suggesting a lot of half elves end up as harlots. The fact that it has an adult warning is probably not required, but it is still kind to volunteer a warning.

Maybe it Ought to be a Retroclone? 

The Dozen Dooms is incredibly ambitious, and aside from a few core concepts like hp, time management, and turn-based dungeon exploration, nearly every rule in B/X Dungeons & Dragons is touched on. Add in a light coverage of those concepts,, throw in an equipment list, bestiary, and a few magic items, and a complete TTRPG is right in front of you.

Cover of 5e Hardcore Mode; Art
by Hankerin Ferinale, ©2020
RUNEHAMMER Games

I can understand why Baldrage chose to instead create a source book, however:

• Firstly, there is a glut of new retro clones. And while The Dozen Dooms would stand out, it creates a lot of signal to noise when trying to reach your audience
• Secondly, this book owes a lot to rules hackers like Professor Dungeon Master. And, this book gives credit where it's due. It owes its genesis to rules hacking, and it makes sense presented as a resource for other people who, like me, share the same passion for the OSR YouTube hacking scene.
• Thirdly, it is very clear that people are hungry for a better game of Dungeons & Dragons at the moment. The success of books like Hankerin Ferinale's 5e Hardcore Mode or Ben & Jessica Dutter's Five Torches Deep speaks to the fact that people want something a little more granular, a little more gritty, and that is sophisticated without being complicated.

What a lot of the Dungeons & Dragons community is getting wise to is the fact that is a lot harder to cut things out of 5th edition than it is to add things to B/X or AD&D. If you want to build a custom game, you are far better off starting with Labyrinth Lord, OSE, Lamentations of The Flame Princess or Basic Fantasy RPG and building up than you are starting with 5th edition and cutting down.

A book of hacks and alternate rules also has the advantage of allowing it to be applied to games that aren't exactly standard issue Sword & Sorcery B/X D&D clones. I could certainly see using some of these rules in modified form with a game like Star Adventurer, or The Wasted Hack. The Dozen Dooms does not confine itself entirely to fantasy, the majority of its rules are valuable across multiple genres.

However, it is my hope that will see Baldrage offer an affordable OSR clone that uses these rules together in a single tight package at some point. If nothing else, to cut down on how many books are at the table

And this dovetails nicely into a discussion who this book is for...

Conclusions

Unearthed Arcana (3rd. Ed.) Cover Art
by Matt Cavotta. ©2004 WotC

If I were to find another book to compare The Dozen Dooms directly to, it would be the Dungeons & Dragons 3e Unearthed Arcana. This was possibly one of the most radical books released in the 3e era. Although it was one that was not the greatest success for Wizards of the Coast, unfortunately, as there was already a movement within the gaming culture towards reducing the importance of house rules and the power of the DM, and an insistence on RAW play

(If you run Pathfinder 1e, this version of UA should be on your shelf!) 

3e's Unearthed Arcana, was entirely a collection of optional rules and tables including some very different approaches to classes, such as bringing back in racial classes and stripping D&D down as far as a three-class game. Many of the rules in The Dozen Dooms I first saw in primordial form in UA, where they no doubt coalesced from the community forums.

The Dozen Dooms, like Unearthed Arcana, is designed for Dungeon Masters who want to tinker with and customize the very rules of the game, rather than just the content in it. switching to a three-class system is radically different from allowing a new prestige class into the game. Turning armor into damage reduction instead of a difficulty to hit as a radical effect on how it plays. As does exchanging spell slots for spell points.

If there is one old manual that I regret parking ways with from that era, it is definitely Unearthed Arcana. The Dozen Dooms has a very similar feel to it. I can sit and browse it, and feel the ideas for a custom system, radically different settings, or a mechanical experiment swirling around in my head, like the vapors from an alchemy lab.

This book is not for DMs who have found the perfect game for them and want to play it unmodified. It's for the DMs who, once they found a rule set that meets much of the criteria they're looking for, are asking what they can do with it to optimize the experience.

If you are running a B/X game and are looking for ways to fine-tune it, I would highly recommend The Dozen Dooms. Likewise, I would consider it strongly as a style guide for people interested in presenting alternative rules, because of the clarity with which these are presented.

I don't imagine anyone who picks it up will find all of the content appealing. I expect, just as the book is presented, that the reader will want to pick and choose some of the material, and leave the rest behind. I think anyone interested in wrenching their own D&D game would find that there's something for them in this book. I personally have already integrated several of the rules as they are written here into my home campaign. And, as I am planning on starting one or possibly two new campaigns in the near future, I will definitely be considering this toolset very strongly to modify Low Fantasy Gaming, ICRPG Core 2e, or Lamentations of the Flame Princess. 

Also, you can expect to see this cited quite heavily in the near future in my Rules Cyclopedia project.