I'm planning to use OSR modules like Caverns of Thracia, Keep on the Borderlands (and new material also as Vornheim) and so on in a open table project I'm running.

I'm not sure whether using Labyrinth Lord or Lamentations of the Flame Princess, and I'm asking you to point the difference between these two systems.

A friend of mine told me that LL is terribly organized. I know that LotFP has no monsters listed but it's no problem because I can take them from other sources. I also know that LotFP is weird fantasy, but this is visible in the related material, not in the main rule book.

I'm referring to the last art-free editions (LotFP 2013, LL 4th release Sept.2009).

What about compatibility with OSR (and old) material like the modules I cited?


3 Answers 3


Most retroclones are very similar. Personally, I use many of them interchangeably, including content from Swords & Wizardry, Labyrinth Lord, LotFP, AD&D, and more. They are so similar, conversion is rarely necessary and it is very simple when it is. So I wouldn't stress compatibility.

Some Considerations for Choosing:

  • The most relevant difference from a compatibility standpoint is that LotFP AC starts at 12 instead of 10 (or 7 instead of 9 in descending AC terms), but adding or subtracting 2 from AC isn't difficult, especially since you will often already be converting between ascending and descending AC.
  • LotFP has different equipment prices for rural and urban areas, the only system I've seen have this is the core rules.
  • LotFP does have a reputation, so even if you're just using the free rules, it will still color the expectations of potential players or even turn them away because LotFP books are often gory and obscene. This is especially relevant to an open table, where you might not have a chance to explain you're just using the rules.
  • For me the biggest consideration was the convenience of an online SRD which is why I went with Swords & Wizardry, and what I'd recommend if you are open to other systems.

If you're not, both systems are free and very similar. I'd say skim through them both, pick the one you like better, grab anything you liked from the other.

Further reading

We have a question with a brief overview of many of the more popular retroclones, but answers don't go into a lot of depth. And an in depth one but it's between Swords & Wizardry and Labyrinth Lord.

  • 1
    \$\begingroup\$ Thank, I hoped in a more in deep analysis but yes, the differences are not so many so maybe this is not really necessary. I ended reading both and I decided for now to use LotFP with parts from LL, mainly the monsters and the underground exploration rules and other tiny bits. LotFP reputation is not a problem since I live in Italy, this system and retroclones in general are mainly uknown here. Thanks! \$\endgroup\$
    – FraNe91
    Commented Aug 22, 2015 at 22:18
  • 1
    \$\begingroup\$ @FraNe91 A quick search for Italian versions revealed one for LL (rpgnow.com/product/68889/Labyrinth-Lord-Italian-Version-no-art) but not one for LotFP, so with that knowledge I'd probably amend my recommendation to LL. I'll try to flesh out my answer with more differences as I get the chance, but I'm glad you found something that will work for you. \$\endgroup\$
    – Barret
    Commented Aug 24, 2015 at 13:50

The single difference that will have the most effect on an ongoing campaign or one shot adventures with characters above 3rd level is in Lamentations of the Flame Princess the only increases to to-hit bonus are received by the fighter. The fighter has a +1 bonus to-hit over the other classes at level one as well.

The result is a 10th level cleric, magic-user, elf, dwarf, specialist (read thief), or halfling fights as though they are first level and fight worse than a first level fighter. This has a huge effect when fighting monsters with very good ACs (2 or less in descending) that are common in higher level modules. If you use Lamentations of the Flame Princess you will probably want to adjust AC more than just the +/-2 difference it has from other OSR games or have a more fighter heavy party.

The second biggest difference is thiefs, called specialists in Lamentations of the Flame Princess. They will be superior to their LL counterparts for most skills at most levels but deficient in one (climbing). At first level their worst score will be 1/6 or 16.67% which exceed their open locks, find/remove traps, and hide in shadows abilities. They also have four pips to increase skills at first level with two more each level after. Thus, it is possible for a first level specialist to have a 5/6 chance (83.33%) of detecting a trap at first level even spreading equally will have two at 2/6 which exceeds LL in all but climb assuming they devote one pip to sneak attack.

Unless points are spent on sneak attack the specialist has none and while one point will double damage the attack bonus is only +2 not +4. Again, you'll need to look at a given module's assumption about thief skills and adjust accordingly.

The others differences listed also need to be taken into account but I consider the changes in to-hit and thief skils keys in running something designed for other TSR D&D influenced games.


Labyrinth Lord is based on the Moldvay/Cook B/X D&D rules, while Lamentations of the Flame Princess is based on the Frank Mentzer Basic D&D rules (the first of the BECMI rulesets). These original rules are very close to each other, but not the same.


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