Aside from small things like layout, art, and the exact wording of rules, what are the major differences between the D&D retro-clone Labyrinth Lord and its primary inspiration, the 1981 D&D Basic/Expert (B/X) by Tom Moldvay?
According to this blog: -
it adds elements from BECMI, and AD&D
The changes it does have [from Moldvay Basic] are relatively minor throughout.
It goes on to outline some of the differences - for example that
The Cleric gains a spell at first level in Labyrinth Lord whereas in B/X and BECMI they did not
and more generally compares the different editions, and how they have been adjusted, combined, or retained.