Deuce Traveler
Adventurer
There have been entire posts covering the differences between 1st and 2nd edition. Despite that, 1st edition and 2nd edition AD&D are very similar; more similar than BECMI D&D is to 1st edition AD&D. Because of that, I believe 2nd edition is simply forgotten about when discussion on editions come up. You could run 1st edition AD&D modules with 2nd edition rulebooks and in a 2nd edition campaign world with little to no tweaking necessary.
You would have to do some tweaking in order to run a BECMI DnD module for 1st or 2nd edition rules, especially when it comes to rules for clerics and demi-humans.
This is how I think of DnD editions:
Chainmail
Original DnD => Gygax/Holmes/Moldvay and Cook/Mentzer BECMI
ADnD => Including 1st and 2nd Editions, Unearthed Arcana, Oriental Adventures and Class Kits
3.5 => 3rd Edition and 3.5 along with associated 3rd party rulesets for d20 system
4E
So for me, 2nd edition has an important mark, but generationally I associate it with 1st edition, just like I would with the various ODnD editions and 3rd edition with 3.5.
You would have to do some tweaking in order to run a BECMI DnD module for 1st or 2nd edition rules, especially when it comes to rules for clerics and demi-humans.
This is how I think of DnD editions:
Chainmail
Original DnD => Gygax/Holmes/Moldvay and Cook/Mentzer BECMI
ADnD => Including 1st and 2nd Editions, Unearthed Arcana, Oriental Adventures and Class Kits
3.5 => 3rd Edition and 3.5 along with associated 3rd party rulesets for d20 system
4E
So for me, 2nd edition has an important mark, but generationally I associate it with 1st edition, just like I would with the various ODnD editions and 3rd edition with 3.5.