One difference, as I recall, was that 1E had the "XP for treasure" system, which 2E didn't. Only the XP tables weren't adjust accordingly, resulting in impossible XP requirements at higher levels. I seem to remember that a magic user would have to kill a dozen great wyrms single-handedly to go from 10th to 11th level.
Sort of. 2e indicated that you should give out story awards for accomplishing an adventure's goal. It was kind of silent on how much to award, except to say that the total story awards shouldn't exceed the amount of XP you can get from defeating monsters in the adventure, and that it shouldn't exceed 1/10 of the amount you need to level up.
However, monster XP was increased by a bit, though this was a bit subtle. In 1e, the amount of XP a monster would give was calculated as follows:
- Find the monster's Hit Dice on the XP table in the DMG, which gives a base value as well as a certain number per hit point.
- For each special ability, add a number of XP to the total. A small number of special abilities are extra-special and give more bonus XP.
In 2e, it instead works like this:
- Start with the monster's Hit Dice.
- Add 1-3 HD per special ability.
- Look the result up on the monster XP table.
Since the table has sort-of exponential (or at least accelerating) results, it means that special ability-heavy monsters will earn many more XP than in 1e. For example, a 1e dao will bring you 1600 XP + 12 XP/hp, for an average of 2068 (8d8+3 hp gives an average of 39 hp). This would seem to be based on the base 600 XP for 8+n to 9 HD, plus two special abilities worth 300 XP each (I'm guessing that's minor spellcasting and immunity to earth-based spells) and one exceptional ability worth 400 XP (which I would guess is the more useful spells they have, like
wall of stone,
rock to mud, and
passwall). The 2e dao has, as far as I can tell, the exact same stats, but is worth 5000 XP – more than twice as much as the 1e dao. 5000 XP is the equivalent of a 15 HD monster, so that's 6 pluses worth of specials (though I can only count four: flying, low-level casting, high-level casting, immunity to earth magic).