u/TheGrolar

(Crosspost from r/osr) I've been working on understanding the math behind OSR level design. I currently run a longform OSE Advanced campaign, but am very familiar with 1e and I think the basic principles hold for TSR-published systems, more or less. I am looking for your thoughts.

We know a few things. One, the 1e system was designed so that a 1st-level character could reach "name" level in a year of weekly four-hour (or longer!) sessions. Two, that experience generally is 25% monster defeats/75% treasure. Three, that ~1/3 of dungeon rooms should be empty and ~1/3 should have a monster, often without treasure.

Now a case study. Gods of the Forbidden North Vol. 3 Ch. 20 is intended for "six to eight" ninth-level OSE characters. It has ~140 rooms. If it is *completely* cleaned out, it will produce ~100k in monster XP and 500k gold exp., roughly 100k XP per character. This will get a 9th level fighter ~80% of the way to level 10, assuming a party of six. (He needs 120k.) Now, the per-room breakdown comes to ~4200 XP per room...though that's an average, with many rooms having 0, less, or more (sometimes a lot more) XP totals.

Here's my question. What do you think an ideal level breakdown comes to? Assume a party explores 6-12 rooms a four-hour session (I've heard a lot of answers to this, but throw in your group's). Call it 8. At this rate, it will take ~18 such sessions in GOTFN to complete the given level, and 22-23 (with another 32 total rooms) for our F9 to become an F10. That's six months of weekly play for one dungeon level, and about two years if groups play once a month (increasingly common). To me, this seems...excessive.

So we come to it:
--How many sessions "feel" right to have a player advance a level?
--How many rooms does your group get through, on average, a session?
--Any thoughts on fixing this?

What does OSE consider an enchanted creature?

OSR (E?) Level Design and Gods of the Forbidden North