In order to avoid a sheer heart attack, or, even worse, a visit to the Doctor's office, I am very drunker on cheap french (resistance) brandy.
Perfect state of mind to write the INTRODUCTION.

To those who exist to bash the OSR, I would almost say: "fuck off", but that would be rood.

Anyway, I am listening to THE FLIGHT OF ICARUS, by IRON MAIDEN. I Hope that Gary is not Daedalus, and, I Hope that I am not Icarus!
The whole entire thing here is a fan edition of D&D, based on the 1e era of Dragon magazine.
Gygaxian wisdom cautions against this, in my interpretation.
A lot of people exist to bash Gary, and, I might be 'noid, but I am pretty sure that there is an Anti-Gary Movement, out there.
One day, I worry that they will start pulling down the statues of Gary.

When Gary talks about Game design, I Listen.
What follows is a carefully contemplated divergence from (O)(A)D&D.
However, at the end of the day, I Hope it is a Game. Nothing more, nothing less.
AD&D is not realism/simulation: it is game school.
I Hope I got an "A" there.

There is BTB/RAW.
Then there is BTM (By the Magazine).
Using all of the Dragon articles as written:
I think the result would be the most complex Game in human history.
Which I think is great, from the point of view of source code.

Now, for actual tabletop play (online or offline), everything had to be simplified to the nth degree.
Why? Game, because. I Hope that I don't offend true (O)(A)D&D fans with the simplicity of things.

There is the temptation to leave my own House Rules out of this, and, to leave Gary's DF/ENW rulings/rules out of this.
My theoretical D&D is of course awesome, deriving from the 1e era of Dragon, but it is less awesome than Gary's game wisdom.
I think that taking Gary Gygax out of D&D is a very bad thing, in terms of Game design.

That said, this is an attempt at a different game, some form of D&D based on the 1e era of Dragon magazine.
If you don't like 0 level characters and critical hit tables, this might not be for you.
Anyway, back to Listening to RIME OF THE ANCIENT MARINER, by IRON MAIDEN.

Keep the concept of Game in mind, and you can't go wrong.
Prespos (John Scott)
October 21, 2021

OUTLINE

THE GAME
It is important to keep Gary's original words here, if only for the purpose of compare and contrast.
This Game requires the 1st Edition MONSTER MANUAL, PLAYERS HANDBOOK, and DUNGEON MASTERS GUIDE.
For campaign play, it is all guidelines, with the final authority resting in the hands of the capable DM.
Realism/simulation is a nice theory, but in practice, the best thing is to start with Game school, overall.
Even then, this D&D is intended to be more realisitc and deadly than 1st Edition AD&D, overall.

CREATING THE PLAYER CHARACTER
Characters begin at 0 Level (Dragon #51), with Method V begin used for all characters.

Like most things from the 11 books and 250 issues, I have simplfied character creation for playability.

0. Choose your race/class
1. Use Method V to generate your class ability scores (Dragon #140)
2. Adjust scores for age.
3. Barbarians: choose a homeland. Rangers: roll to determine your home climate/terrain.
All classes: at 0 level, you have no class abilities.
Wizards have the spells Read Magic and Cantrip at 0 level.
Illusionists have the spells Read Illusionist Magic and Cantrip.
Priests have the spell Orison at 0 level.
Druids have the spell Orison at 0 level.
4. Choose alignment. Assassins may switch to a Good alignment for 1000 XP.
5. Skills. A simple skill system is used. 1 skill per point of INT above 10. 1 skill per level.
The secondary skill is a free skill.
Different types of skills: weapon skills, non-weapon skills, languages.
Certain skills have been removed from the Game, replaced with Skill Classes.
Any race can multi-class a Skill Class. There is a limit of 4 classes, when it comes to Multi-Classing.
Armorer, Blacksmith, Weaponsmith: Use the Smith class instead (note that this class is intended for humans only: dwarven and gnomish smiths are more powerful).
Bow Specialization: Use the Archer class instead.

CHARACTER ABILITIES
These are described in Dragon #107.

STRENGTH
+1 STR for male characters, -1 STR for female characters
increase female STR limits by 1 or by 0.25% if in the 18 range
many monsters are assigned STR scores

INTELLIGENCE
intellgent monsters can be dangerous opponents (Best of Dragon V).
for every point of INT above 10, the character gains 1 skill
intelligence affects training time, when advancing in level

WISDOM
As is.

DEXTERITY
As is.

CONSTITUTION
+1 CON for female characters, -1 CON for male characters
0 level characters begin with HP = CON

CHARISMA
Max. # of Henchmen becomes Max. # of Figures
Figures are: Henchmen, hirelings, animals, familiars, followers, charmed and/or fascinated NPCs and/or monsters, animated undead.

COMELINESS
Comeliness of 18+ allows a character to fascinate others.
Comeliness can be broken down into 3 sub-abilities: Face, Body, Voice (Dragon #63)

PERCEPTION
Dragon #133.
Perception affects surprise, the ability to detect the invisible, the ability to see through illusions, and other things.

ABILITY TRAINING
1 week + 100 gp = +01%
Ability scores cannot be raised above race/gender limits

CHARACTER RACES (30)
Aaracockra (Dragon #124)
Centaur
Dwarf (Hill, Mountain, Grey)
Elf (High, Aquatic, Grey, Valley, Snow, Sylvan, Wild)
Gnome (Deep, Surface)
Goblin (Dragon #141)
Kobold (Dragon #141)
Half-Dryad (Dragon #109)
Half-Elf (Half-high, Half-aquatic, Half-grey, Half-valley, Half-snow)
Half-Ogre (Best of Dragon IV)
Half-Orc
Half-Satyr (Dragon #109)
Hobbit (Hairfoot, Tallfellow, Stout, Mixed)
Orc (Dragon #141)
Uldra (Dragon #119)
Xvart (Dragon #141)
Human

No monster PCs, beyond those listed above

CHARACTER CLASSES (64)
BUREAUCRAT
Bureaucrat
Politician
 

CLERIC
Priest (may use the weapon of the deity, minor spells/powers relating to the deity + 2 new abilities: sacrifice, convert)
Barbarian Priest (Dragon #109)
Druid (roll 2d6 when praying for spells) (Get Dragon #119)
Nun/Friar (Best of Dragon Vol. IV)
Shaman (Dragon #141)
Mystic (Adventures Dark & Deep)

ENTERTAINER (Juggler, Acrobat, Troubador) (Dragon #69)
 

FIGHTER
Archer (Best of Dragon III)
Barbarian (revised, Dragon #148)
Capoeira Dancer (Battle Dancer)
Berserker (Dragon #133)
Fighter (certain skills can only be chosen by fighters)
Ranger (many skills, more than any other class)
Archer-Ranger (Best of Dragon III)

FIGHTER / CAVALIER
Knight (revised, Dragon #148), Elven Knight (Dragon #114)
Paladin
Anti-Paladin
MAGICK-USER
Wizard
Diviner
Illusionist
Necromancer (Death Master: Best of Dragon IV)
THIEF
Thief
Assassin (new ability: Forgery, Dragon #96)
Bandit
MONK
OTHER
Psionicist
HUMOROUS
Accountant
Hopeless
Jock

ALIGNMENT
As is.

SKILLS
Proficiencies are referred to as skills. 
AD&D is class-based, not skill-based. 
A SSS (Simple Skill System) is used. 
For every point of INT above 10, the character gets 1 skill. 
For every level the character has, the character gets 1 skill. 
0 level characters check for a secondary skill, and get 1 bonus non-combat skill. 
Any 1e skill, combat or non-combat, from a 1e source is available. 

Certain skills are not available: 
Bow specialization (use the Archer class instead) 
Armorer, Blacksmith, Weaponsmith (use the Smith class instead)

HOUSE RULES
The campaign uses the 11 Official AD&D rule books + the 5 Best of Dragon magazine compilations. 
As a general rule of thumb, Dragon magazine articles are not used. 
Exceptions are articles written by Gary Gygax, and, Sage Advice. 
Listed house rules are most often derived from the posts of Gary Gygax over at Dragonsfoot and ENWorld. 
The 11 Official AD&D rule books (expanded) are all in .html form. 
Players, please only access these books: PH, UA (Players Section), OA, DSG (Players' Section), WSG (Players' Section). 
Not referecing the DMG and other DM sources will enhance the mystery, and, therefore, fun for you as a player. 

MM 
Large monsters: +1 hp per full Hit Die, +1 damage per 2 full Hit Dice. 
Small monsters: -1 hp per full Hit Die, -1 damage.

Energy Drain: a d10 table is consulted, constructed from REF5 Lords of Darkness. 

Dragons: Dragons are deadlier (FR0). 

PH
CREATING THE PLAYER CHARACTER
Characters begin at level 0. I've simplified the system in GHA (Greyhawk Adventures). 

STRENGTH 
Increase female STR limits by 0.25 or by 1.