At least part of the purpose of a 0-level funnel is to make clear what happened to these particular characters, that they can never simply go back to working fields or scaping out garderobe middens. Well, this adventure is going to accomplish that, and how it ends will set the tone, in all likelihood, for the PC's careers (at least in the short term).
Another thing the funnel can accomplish is to ensure players understand that the game will kill you if you act without caution and that you are not guaranteed any sort of balance. Oh, and that the universe is full of weirdness, with other planes of existence far closer than you think. This funnel accomplishes all of those things as well.
Actually, this funnel introduces Dungeon Crawl Classics amazingly well, and I predict that it will join Sailors on the Starless Sea, Hole in the Sky, and Frozen in Time as a fan favorite.
As long as you’ve known of the flame-licked caves and suffocating caverns, they have been forbidden to your people. But three days ago the Black King and his brigands overran your small hamlet, taking friends and family hostage. His demands are as simple as they are impossible: Venture into the burning caverns and return with the secret of eternal life.
Now, standing before the seething fissure, armed with only your simple tools and desperate courage, you must accomplish what an army of blackguards cannot. The Well of Brass awaits.
Designed to be run in a single session, this introductory 0-level module wrenches your PCs free from their humble lives and casts them into a world of high adventure. Many will perish amidst the strange mysteries, weird foes, and forgotten magics, for only the most courageous and cunning of reavers can emerge from Beneath the Well of Brass.