I was in a discussion in the comments over at The Angry GM, and mentioned that I use 4e to play an older-style game. And someone asked me whether the system got in the way, to which I answered
I don’t find the system gets in the way. Once I figured out how the system actually worked, as opposed to how the designers kept telling people it worked, I was able to design all sorts of game elements and make them behave consistently.
At which point someone else asked how 4e “actually works”. Which requires a much more involved answer than I can give in a 2,500 character comment.
The thing is, I did not have a single epiphany that described the whole system at once. Rather, I figured out each mechanic and subsystem separately as I was trying to design a particular element or achieve a certain result. Its more than a single post is worth, in fact how 4e actually works is what this whole blog would be about if I ever had time to post to it. But perhaps it is time to try to find a common thread among the various game elements and try to describe the overall flavour of the system, once it is uncoupled from the baggage of WotC’s presentation of it.
Like the other iterations of D&D, 4e is a resource based attrition game. Resources that have mechanical effects are gold (except in 5e where it is worthless unless you engage in domain play, for which there is no support that I am aware of), consumable magic items, spell/daily power slots, and hit points (more on this in a 4e context below).
Gold, and residuum in a 4e game, is used in editions 0-4 to purchase other game elements for use in play. Originally I believe this only really came into play in domain-style games where you built strongholds and constructed castles, but by 1e the acquisition of gold was necessary to level because you had to purchase training. By 3e you could use it to purchase and construct magic items. In 4e you can also use it to cast rituals. Magic treasure either provides a particular game element or is converted to cash.
Most other resources are replenished on a daily basis. Vancian spells and 4e daily powers, for example (theoretically in 1e it could take longer for a high level wizard to replenish her full battery of spells, but I don’t know anyone who played that way). But also hit points and healing surges. Even in old-school games only low level characters had to rely on natural healing; clerics and healing potions made hit points a daily resource augmented by consumable magic items.
So at the core, you use cash to purchase consumable or upgraded game elements, and you repair damage and replenish your most powerful game elements on a more or less daily basis. You are therefore trying to acquire cash and magic items (and experience) to grow more powerful, and it is necessary to nurse your daily resources to do so.
Probably the most significant difference between 4e and earlier editions is the use of rituals. Most rituals are a cash resource, more akin to a consumable item where you have a menu of effects to choose from at the time you consume it, although some rituals use the daily resource of healing surges.
So in most versions of D&D, from a purely mechanical standpoint, adventure design involves forcing the players to make decisions about how to allocate their daily and cash resources. And that fact that it isn’t only the cleric and the wizard that have daily powers, or that damage recovery is measured in blocks of hit points (healing surges) instead of individual hit points doesn’t really make a difference. The game basically plays the same. Except for one very significant difference, which is common in editions 3-5: the acquisition of experience.
In 0-1e, and optionally in 2e, experience was awarded for the acquisition of cash treasure in much greater proportion than it was awarded for combat. This meant that finding treasure without engaging in combat was a viable option, because it reduces risk and conserves daily resources so the party can continue to seek treasure. This is very different from later editions where combat is the primary means of acquiring experience, which encourages a playstyle where combat is nearly always the best way to gain treasure. This is the only element of 4e that absolutely requires a change in the rules as written to adopt an old-school playstyle, in order to make either cash or some other goal-achievement metric into the primary method of obtaining experience.
That probably sums up the core similarity, but I want to give a nod to one 4e mechanic that gives DMs a lot of flexibility in replicating an old school experience, and that is the disease mechanic. WotC only applied the disease mechanic to diseases until very late in 4e’s run when it was also used for curses. But there is no reason why it cannot be used to duplicate any long term status effect. I have used it to mimic the effects of old school ghoul paralysis, as well as to physical injuries, and some poisons. For those of you familiar with the mechanic, there is no reason why it has to key off endurance, or why the skill check must be made every extended rest instead of every short rest, or ten minutes, or one week. There are already rules for how such “diseases” can be contracted, including how to get them during combat. So if you are trying to convert an old school monster or module and want to know how to create an effect that lasts longer than “save ends”, see if you can make creative use of the disease mechanic.
Campaign Under Deconstruction 