Here are the attack progressions to hit Armor Class 2 by level for ten games--the three major OD&D versions and seven contemporary clones:
Dungeons & Dragons (0e) (1974-78)
Advanced Dungeons & Dragons (1e) (1979)
Moldvay Basic/Cook Expert Dungeons & Dragons (B/X) (1981).
Labyrinth Lord (2007)
Swords & Wizardry (2008)*
Swords & Wizardry White Box (2009)*
Lamentations of the Flame Princess (2010)*
Seven Voyages of Zylarthen (2013)*
Delving Deeper V4 (2014)
Those with an asterisk list things in attack bonus form rather than table form, but for the sake of this comparison all will be listed in table form.
For OSRIC I used version 2.2. I assume the numbers are the same across all versions but I may be wrong on that. For Swords & Wizardry I used the recent 'Complete' edition, which may or not have different numbers from the original 2008 edition. The numbers for Delving Deeper are from the most recent edition, which differ somewhat from those of earlier editions.
I hope I didn't make any mistakes.
Looking at the tables a number of things leap out. Some things were not surprising. Some were.
I'll make some comments tomorrow. But I welcome any comments or observations anyone would like to make.
(If you turn your phone sideways, I think these will exactly fill up the screen. You probably already knew that. But I didn't.)
To Hit Armor Class 2: