So a more heroic style of play comes into effect in a very uneven progression - the characters reach a zone where they're just hard to hit.
(Monsters usually hit better ACs on dice rolls less than 20 to compensate).īut players are also more likely to get into the rarefied air of super-low ACs than monsters, and so are more likely to break 'the sound barrier' as it were, where only a nat 20 plus the bonuses a monster is unlikely to have will attrite the players' hit points (and indirectly spells, potions, and other resources). So if they get a natural 20 then they're likely to hit a much better AC than the monster. Players are far more likely to have bonuses coming in from all over - ability scores, magic weapons, spells like prayer, plus all the situational modifiers AD&D envisioned for things like higher ground, etc. The note on page 82 is an example of a rule that helps the player but isn't presented as a player-helper.