Koren n'Rhys
Explorer
No particularly meaningful differences between BX and BECMI, no. BX was published in 1981 as two boxes (Basic 1-3 and eXpert 4-14) and is also referred to as "Moldvay/Cook" for it's editor/authors. Tom Moldvay and Zeb Cook for B, then Cook and Steve Marsh for X. It only runs 14 levels and features race as class for Elves, Dwarves and Halflings.I am confused. What is the difference between all these different editions of Basic D&D? Anything truly significant with regards to Classes, Races and Monsters? Curious minds want to know.
BECMI was a reworked version released starting in 1984 as a revised version edited by Frank Mentzer. It was expanded to cover 36 levels over 4 box sets (Basic 1-3, Expert 4-14, Companion 15-25 & Master 26-36) and also added in a lot of additional options for domain level play, weapon mastery, additional spells, monsters, magic items, etc all to support those higher levels. A fifth box, Immortal, offered a higher tier where you essentially play as gods. The popular Rules Cyclopedia book combined the BECM content into a single hardcover but didn't cover I.
B and X/E are essentially identical between the versions. The big difference is in the progression of the percentile thieves skills, which by being stretched over 36 levels rather than just 14 really cripples low level thieves in BECMI. Even Mentzer acknowledges he messed that up.