Semi-sorta playtested last year when I ran some Dark Sun using these house rules. Some of them are old, dating from the 80's when I first ran 2nd ed, and some are new. Weapon and armor breakage I only use for Dark Sun games.

ROLLING STATS
Dark Sun games use the stat rolling method in the boxed set.
STATISTIC MODIFIERS
Use the revised house rule tables for stat bonuses and modifiers.
ROLLING HIT POINTS
Maximum possible hit points at first level.
2nd level: Roll twice and take highest result.
3rd level+:  Roll as normal.

DEMI-HUMAN LEVEL MAXIMUMS
Use prime requisite modifiers to maximum level limits.
Demi-humans require double normal experience to advance beyond their level limit.
SPELL SLOTS
Wizards and Priests may choose the spell to cast at the time of casting. They do not have to memorize spells, but do otherwise obey the spells per day limits.
Wizard bonus spells.
Wizards get bonus spells for exceptional intelligence in a similar way as Priests that have an exceptional wisdom score. Reference the revised house rule tables for wizard bonus spells.
WEAPON PROFICIENCIES
Wizards and Rogues may take proficiencies with any weapons. They must use the NWP penalty, and the number of available proficiencies as normal.
Priests must use the weapons and armor as described by their diety.
The following classes/races may add their Dex modifier to ranged attack damage:
Fighters with weapon specialization.
Elves and Rangers with Bows.
Rogues with thrown weapons.
ASCENDING TO HIT AND ARMOR CLASS
Use ascending values for armor class and THACO is replaced with Attack Score.
To convert values:
Subtract AC from 20 to determine ascending armor class.
Subtract THACO from 20 to determine Attack Score.
ROGUE ABILITIES
Rogues abilities are treated as non-weapon proficiencies.
Do not use Thieving Skill Base Scores.
Thieving Skill Racial Adjustments, convert percentile by dividing by 5.
Theiving Skill Dexterity Adjustments are not used. This modifier is determined by the NWP values.
Pick Pockets: Dex.
Open Locks: Dex.
Find/Remove Traps: Dex.
Move Silently: Dex.
Hide in Shadows: Dex.
Detect Noise: Wis.
Climb Walls: Str.
Read Languages: Int.
Thieving Skill Armor Adjustments are used. Convert percentile by dividing by 5.
Rogues get 4 points per level, including 1st level, to add to their skills. No skill may be increased by more than 1 point per level and these points are only used for the rogue special ability skills.
Bards get 2 points per level, including 1st level, to increase their skills. They also may not increase a skill by more than 1 point per level, and these points are only used for the rogue special ability skills.
Non Rogues may take rogue abilities, except for Read Languages. They are classified as rogue non-weapon proficiencies, and take 1 additional NWP slot to purchase. Additionally, a non-rogue taking a rogue special ability is at a -2 check modifier.
NON-WEAPON PROFICIENCIES
Non-weapon proficiencies are purchased with NWP slots as normal.
NWP checks are performed by rolling a d20, adding the characters relevant stat modifier, check modifier, and any situational modifiers. This is compared to a difficulty target number determined by the DM.
Easy task: DC 10   (level 1-4)
Average task: DC 15   (level 5-8)
Difficult task: DC 20   (level 9-12)
Heroic task: DC 25   (level 13-16)
Legendary task: DC 30   (level 17-20)

EPIC CREATURES
To simulate a creature that can combat more than 1 foe at a time, and still provide a challenge for a group of players, use the epic creatures rule.
Epic creatures have a value. Epic 2, Epic 3, etc...
Epic creatures multiply their hit points by their epic values.
Epic creatures have a minimum number of attacks equal to their epic value. If possible, an epic creature must attack different targets with each attack.
Epic creatures get a bonus to saving throws equal to their epic value.
Multiply the XP value for an epic creature by it's epic value.
Do NOT increase an epic creatures AC. Characters should still be able to hit it at it's original HD value.
Epic creatures tend to have better treasure than normal types. DM discretion.


CRITICAL HITS
An attack roll that hits it's target, and is also a natural 20 is a critical hit.
An attack roll that does not hit it's target, but is a natural 20 is an automatic hit.
Automatic hits roll damage as normal, and have no further effect.
Critical hits deal maximum possible damage, plus the roll of a damage dice for the weapon. Count bonuses for weapon plusses, Strength, etc only one.
Ex. A +1 longsword wielded by a Fighter with an 18 strength, deals 12+1d8 damage on a critical hit.
Fighters score a critical hit on a natural 20. Their chance for a critical hit increases as they gain levels.
Level 1-7:   20
Level 8-13:   19+
Level 14+:   18+
Paladins and Rangers do not get this critical increase. Gladiators in Dark Sun do get this crit increase.
A rogue that performs a sucessful backstab is a critical hit, regardless of the natural number rolled.


CRITICAL FUMBLES
A natural attack roll of 1 automatically misses.
A natural attack roll of 1 that also misses it's target after bonuses is a fumble.
On a fumble, the attacker loses their next attack or action. If they have multiple attacks available, they only lose one attack, not all available attacks.
Weapon and armor breakage.
On a fumble, the weapon used must make a save versus crushing blow. On a failed save, the weapon is damaged. Damaged weapons count as a club for dealing damage (1d6) and are at -1 to attack rolls until repaired.
If the attacker rolls maximum possible damage on the dice, the weapon used must make a save versus crushing blow. On  a failed save, the weapon is damaged.
On a critical hit, if the target is wearing armor, the armor must make a save versus crushing blow. On a failed save, the armor is damaged. Damaged armor provides half it's AC bonus until repaired.  (Round down to a minimum of 1) Damaged armor that is damaged again is destroyed. The armor is rent and broken to be useless.
Natural weapons and armor are not subject to weapon breakage rules.

I'm more interested in how you'll handle movement and such. I've basically converted my grids from 5' on a side to 3.3' on a side--in 2nd edition, 9 medium creatures can fit in a 10' square, as opposed to the 4 of later editions.

It makes a big difference with spell area affects, among other details.

Combat movement is another big deal--you're moving 2, maybe 4 squares a turn in typical 2nd Edition situations, while 6 or more, sometimes MUCH more, is common.

Quote from: Doom;1027823I'm more interested in how you'll handle movement and such. I've basically converted my grids from 5' on a side to 3.3' on a side--in 2nd edition, 9 medium creatures can fit in a 10' square, as opposed to the 4 of later editions.

It makes a big difference with spell area affects, among other details.

Combat movement is another big deal--you're moving 2, maybe 4 squares a turn in typical 2nd Edition situations, while 6 or more, sometimes MUCH more, is common.

Are you using PO:C&T? Usually it depends on indoors vs. outdoors in my games, as Mv is in x10 feet indoors and x10 yards outdoors.

Quote from: Doom;1027823I'm more interested in how you'll handle movement and such. .

For 2nd ed I usually don't use minis or grids

What's PO: C and whatever?

And I'm pretty motivated to use minis and a "grid", as I have lots of DDM and many DF pieces.

AD&D Players' Option: Combat & Tactics. (Often referred to as the book foreshadowing AD&D 2.5e into 3e.)

Ooh, thanks. Heard of it, never got it. I think it came out in sad years after grad school and before I had another gaming group.

Interesting. Equally interesting that someone still might play 2e.

Quote from: RPGPundit;1028124Interesting. Equally interesting that someone still might play 2e.

I've come to the realization that it's the edition I prefer. "My" edition, so to speak. I may play 5th if I get a chance, but I'm pretty much happy using 2nd edition when I DM.

Quote from: Ratman_tf;1028159I've come to the realization that it's the edition I prefer. "My" edition, so to speak. I may play 5th if I get a chance, but I'm pretty much happy using 2nd edition when I DM.

I suspect you're in a minority. Was it your first system?

Quote from: RPGPundit;1028415I suspect you're in a minority. Was it your first system?

Nope. Started with Moldvay Basic, then AD&D and then 2nd ed.

Wasn't mine either. D&D, next AD&D, then Palladium, FASA Mechwarrior, Shadowrun, WEG SW, WW Storyteller, CoC, IN SJG.... and finally to AD&D 2e. Then bounced around some more again until I came back to AD&D 2e. To this day the best games I played in are in AD&D 2e, by far.

It offered everything I wanted, cleanly, with extra options as desired. Great toolbox! Will play again!

Quote from: Ratman_tf;1028453Nope. Started with Moldvay Basic, then AD&D and then 2nd ed.

Huh. Weird.