This is part of my ongoing series dissecting early Dungeons & Dragons, and building my retroclone Dungeon Raiders out of it.
Leveling up is central to early D&D, so a retroclone must include some manner of handling it.
In Original D&D, each class levels up at a different rate (fighters every 2,000 XP, magic-users every 2,500 XP, and clerics every 1,500 XP), and this rate is exacerbated by the character’s prime attribute. A fighter with a high strength score would gain XP at an even higher rate than normal, while a cleric with low wisdom would gain XP more slowly.
The same concept exists in Basic D&D 1E and AD&D, just with more classes.
This is not arbitrary. In OD&D, clerics at first level have access to no spells, and at higher levels are gaining spells similar to the magic-user’s, so their faster level progression allows them to become effective early on. Meanwhile, magic users start out weak but become very powerful, so their slower level progression prevents them from completely overpowering other classes early in the campaign.
This also helps to make each class distinctive. Each player must pay attention to his or her own character’s XP, and leveling up becomes a more personal experience, since it happens to one character at a time.
But what of the cost? Unequal progression is fine if the player-characters all started out at the same session, but what happens when a new player joins the group? Is his level 5 magic-user on par with the level 4 fighter and level 6 cleric?
Worse, which spells are those wizards casting? It becomes much more difficult for the DM to plan encounters when everyone’s at a different level.
So here’s where we bring in more modern design wisdom. Each character levels up for every 2,000 XP that the character earns. XP is earned for each gold piece recovered, and for each monster defeated (calculated as the monster’s starting HP times ten). XP is awarded to the entire party, then divided equally to each character.
What do characters get for leveling up? In old D&D, not much: magic-users and clerics get access to new spells, while all characters gain more hit dice. However, all hit dice must be re-rolled, so you may roll high at first level and low on second level, ending up with fewer HP at level 2 than at level 1.
This, too, is not arbitrary. This is why loot was so important in early D&D; the difference between a first-level fighter and a tenth-level fighter was primarily a matter of his equipment.
However, we’ve moved on. We’ve seen the problems with this approach; players drool over weapon lists, becoming intensely attached to their +2 swords. This is fine to a point, but quickly turns into a game focused on finding weapons.
We will ameliorate this lust with two bonuses on leveling up: +1 on all attack rolls, and instead of re-rolling all hit dice, players simply roll 1d6 and add this to their HP total. You can still have fighters weaker than wizards at high levels, but less dramatically than in OD&D, and the differences between each class will even out over time.
Enough! In the next article, I’ll cover the rest of a character’s stats: ability scores, skill checks, and alignment.