OSR Retroclone Comparison

RETROCLONE COMPARISON

TSR GAMES
----------
Original Dungeons & Dragons
Free?: Out of print, technically no
The original game of adventure, created by fusing Arneson's fantasy Braunstein campaign with Gygax's Chainmail medieval combat rules. OD&D is relatively short and has rules that generally require a great deal of interpretation due to the way it grew out of actual games. Compared to all other games after it, OD&D has the least degree of statistical granularity - most damage rolls are d6, while stat bonuses never get greater than +1.

Basic/Expert (B/X)
Free?: Out of print, technically no
"Basic" Dungeons and Dragons was the result of a third-party author, John Eric Holmes, approaching TSR during the development of AD&D and offering to rewrite OD&D into an introductory version. TSR thought a "Basic" set with simpler rules for levels 1-3 would help ease players into the "Advanced" line and took him up on the offer. The Basic rules continued to be updated afterwards, with later versions by Tom Moldvay (Moldvay B/X). Confusingly, TSR later released an "Expert" version of the rules (written by David Cook), as some players preferred the Basic rules to the Advanced version and wanted to continue past level 3 rather than transferring their campaign to the Advanced ruleset.

Key features
-Greater impact of character attributes: bonus modifiers go from +1 at 13 to +3 at 18
-race-as-class
-descending AC with unarmoured AC at AC9
-some weapon variation, with damage die using d4/d6/d8/d10
-To-hit rolls formatted as a table
-encumbrance measured in the very cumbersome "coins"

Advanced Dungeons & Dragons (AD&D, sometimes 1e or 2e)
Free?: Out of print, technically no
After the popularity of OD&D, Gygax revised OD&D's rules, adding new complexity. AD&D 1e is sprawling, huge, and an organizational mess - debates still occur about how to resolve initiative in the system as written, and much like OD&D some interpretation of the ruleset can be required. The later 2nd edition revision improved the organization considerably.

Key features:
-Percentile strength
-higher granularity in stat bonuses (rather than a uniform +1, the bonuses granted by high strength would be different based on different tasks)
-separation of race and class
-descending AC, with unarmoured AC at AC10
-considerable weapon and armour variation, with a range of different damage dice for different weapons and different damage dice rolled based on size of target. Optional subtables show different interactions between
-to hit rolls listed as "THAC0", which outputs fundamentally similar results to a lookup table but saves space
-large number of subsystems and different dice rolling methods
-large number of published settings
-Gold for XP is a feature of 1e, but 2e introduced alternative XP advancement rules via "class actions", which is widely regarded as a cutoff point for the "end" of dungeoncrawl play.
-2e also introduced optional "nonweapon proficiencies"

Basic/Expert/Companions/Masters/Immortals (aka BECMI or Rules Cyclopedia)
A further expansion of the Basic/Expert system into 5 box sets. Along with the existing "Basic" (level 1-3), "Expert" (4-14), there was now a "Companion" (15-25), "Master" (26-36), and "Immortal" (36-godhood) tier of play. These 5 boxsets were later compiled into a single book, the Rules Cyclopedia, by Aaron Allston (better known for his Star Wars X-wing novels).

Key features:
-Mostly identical to B/X; differences of course being mainly in support for B/X style play up to level 36 and beyond.
-Immortals rules instead provide for character advancement through divine ranks.

RETROCLONES
-----------
Generally speaking you can divide retroclones into two types. Type A retroclones are written mostly to get around copyright restrictions: rules may not be copyrighted, but their specific wording may be, under American copyright law. Type A rulesets generally attempt to reproduce a TSR ruleset faithfully, with some interpretation included. Type B retroclones are often based on a TSR ruleset but introduce significant variation to better fit a particular theme or tone. Some retroclones certainly aim to do both, so this is by no means a rigid typology. As a general rule most retroclones use Basic/Expert as a base, due to the popularity and relative simplicity of the system compared to AD&D, but there are exceptions.

Type A Retroclones
---------------------------
Labyrinth Lord (LL)
Free: Yes, No-Art version
Labyrinth Lord is a restatement of B/X using different language as to avoid copyright.

Old School Reference and Index Compilation (OSRIC)
Free: Yes
OSRIC is a restatement of AD&D 1e, made to "provide publishers with a tool to legally produce gaming materials compatible with Advanced Dungeons and Dragons".

Swords & Wizardry White Box
Free: No?
A rewrite of OD&D. Features a similar lack of granularity in mechanics; attributes have no effect (at most +1 if using optional rules) aside from granting increased experience. Not to be confused with Swords and Wizardry Complete, from the same publisher (which is free). Most of the time "S&W" refers to Complete, not White Box.

Type B Retroclones
--------------------------
Basic Fantasy RPG (BFRPG)
Free: Yes, Player Rules
BFRPG is mechanically most similar to B/X but borrows a few conventions from AD&D, mostly in the separation of race and class.
-attack bonus and ascending AC
-race and class, although races do have class limitations as per AD&D
-slightly more frontloaded thief skills compared to B/X (usually up by about 5-10% per category)

Lamentations of the Flame Princess (LoTFP)
Free: Yes, Player Rules
LoTFP is a free ruleset targeted at "weird fantasy roleplaying". The line is more focused around the modules and the rules are mostly based on B/X and shares many of B/X's features. Key features include:
-no attack progression except for fighters
-noncombat actions represented as d6 checks
-replacement of the Thief with the Specialist, who handles skills on d6 checks.
-ascending AC and attack bonuses
Overall LoTFP provides a very stripped down B/X that is suitable for many different kinds of campaigns, but has a very low level of granularity. PC power relative to other retroclones is very low. Publishing line features many modules with an emphasis on historical scenarios or horror.

Adventurer Conqueror King (ACKS)
Free: No
ACKS is a ruleset focused on the implicit progression in classic D&D from dungeoncrawling adventurer, to wilderness conqueror, to ruling king. Out of all retroclone rulesets it has the most built-in support for end-game domain play. Other major features:
-mostly identical to B/X, but with a larger number of class options and racial class options (demihumans get unique classes)
-noncombat actions represented as d20 checks
-optional noncombat proficiencies, which are similar AD&D2e NWPs and 3.x Feats
-ascending AC with to-hit numbers
-Fighters receive damage bonuses and Cleaving mechanics. Magic Users cast from a carefully selected repertoire (similar to 3.x Sorcerer, but with the ability to change the repertoire given time and cash)
-"stone" encumbrance (somewhat simpler than LoTFP's version)
ACKS provides a more detailed B/X experience that supports all tiers of play. PC power relative to other retroclones is slightly higher. Publishing line focuses more on "GM/campaign resource" books - the Player's Companion provides useful rules for custom-building B/X style classes, while Lairs & Encounters provides what the title suggests.

Swords & Wizardry Complete (S&W)
Free: Yes
A relatively unique system that's an evolution from OD&D with a path taken somewhere between B/X and AD&D. Features:
-generally lower attribute modifiers, but with more granular modifiers as per AD&D
-inclusion of many AD&D classes and options
-encumbrance in pounds

Dungeon Crawl Classics (DCC)
Free: No
DCC is often included in OSR typologies due to the dungeon crawling focus but draws much more from a 3.x D&D rules base. Major features include:
-infamous for "level 0 funnels" - one game option for a new campaign is to have each player roll multiple level 0 commoners and go through a prepared "funnel adventure" - the guilt-ridden survivors become level 1 adventurers.
-usage of zocchi dice, requiring either a digital dice roller or the purchase of non-standard die sizes
-Mostly B/X attribute bonuses, but with some granularity in specifics as per AD&D
-"Mighty Deeds" ability for fighters
-non-Vancian casting - spellcasting is instead determined by successful, with the degree of success determining power of the spell and/or any complications that occur
-spell complication tables provide many methods of making magic strange and icky
-3 save system similar to 3.x
DCC is comparatively unique; compared to other retroclones DCC PCs are considerably higher strength.