LotFP uses the same 6 ability scores rated 3-18 as BX. All ability modifiers use the -3 to +3 range as per Strength modifiers, i.e. no separate track for -2 to +2 for initiative adjustment or reaction rolls.
You begin generating a PC by rolling 3d6 in order, just as the Good Lord intended. BX allowed for a 2 to 1 point swapping deal, where you could penalize your fighter 4 points of Intelligence to gain 2 points of Strength. Instead, LotFP allows any two scores to be swapped. I like that allot. Less fiddly math without the pure anarchy of arranging the numbers as you please.
Here are some key differences in how the six stats work in play:
Charisma [This is the order they appear in LotFP.]
- Charisma does not modify Reaction Rolls. Big change, if you ask me.
- Charisma does not set the base morale of retainers. Rather, it modifies a die roll that sets the morale score for newly hired NPCs.
- No maximum number of retainers. In fact, building a large household staffed with all sorts of people gets its own chapter in the rulebook.
- Pretty much the same as BX.
- Mostly the same as BX, but instead of Dex granting an individual initiative modifier, the standard -3 to +3 Dex mod is used as a tie-breaker when rolling individual initiative.
- Instead of everyone knowing a flat number of languages and Int modifying this number, there's a Linguistics skill that starts at 1 in 6, which the Int modifier can raise. Upon encountering a language for the first time, roll Linguistics to see if your PC happens to know it. The Linguistics rules also specify that anyone with an Int of 7 or more is considered literate.
- Modifies saves versus magic-user spells (both the caster's and the target's modifiers apply!)
- Shortens/lengthens times for MU research activities
No major changes.
- UPDATE: Viktor Haag rightly points out that, unlike BX and darn near every edition of AD&D since the 3 little beige books, Strength mods do NOT apply to damage rolls. That certainly qualifies as a major change and points towards the overall flattening of the power curve in LotFP. I apologize for the oversight. Apparently I was too busy double checking that the Open Doors rules were largely the same in LotFP and got sloppy on the rest. The Open Doors roll is one of my all-time favorite D&D mechanics, because one minute the party is slaying demons and dragons like heroes and gods of old and the next minute they can't get the refrigerator open. I love that shit.
- Modifies all non-magic saving throws.
- Modifies saves versus cleric spells (both caster's and target's mod applies)
- Shortens/lengthens times for clerical research activities.
Completely absent is the concept that high scores in your class's prime requisite should earn you an experience point bonus. Good. That was a vestige of OD&D back when high stats didn't actually do all that much for you. Nowadays it's just double dipping.
I should note that, just like the earliest version of D&D, no real provision is made for scores above or below this normal human range, as the ethos of Raggi's game eschews imagining inhuman monsters or extra-planar beings as Just Like PCs But With Higher Numbers.
BX has an optional "hopeless character" rule where DMs were encouraged to allow a character with all below average scores or 2 or more scores of 3-6 to be thrown away in favor of a new set of rolls. LotFP's version of this is to total the six ability modifiers. If the number is below zero, trash the character and start over. This rules is not listed as optional.
Another optional rules in BX concerns starting hit points. If a new PC has only 1 or 2 hitpoints, the DM can allow a reroll. LotFP comes with a non-optional minimum hit point chart. If you roll lower than the minimum, you get the min instead. The minimums are:
Fighter - 8 hit points
Dwarf - 6 hit points
Magic-User - 3 hit points
Everyone else - 4 hit points
Note that Fighters get d8 for hit dice, so basically I Get All The Hit Points is a class ability for first level fighters. Everyone else has to throw dice.
Okay, that's enough for now.
(Just kidding about the Objectively Best Rules comment. Also, I'm confidant that James looked at other versions of D&D when he wrote LotFP.)