So, here's the deal. I'm DMing this campaign for a long time using the Brazilian scenario called Tormenta. They have 20 superior gods for the world of Arton. My players are about to get to the epic tier in D&D 4e and I decided to make it as epic as possible for their level. So I'm rewriting an adventure that has a nice theme, but is a brainless hack'n slash in the original.
The idea of the adventure is, they're going to free Valkaria, the godess of ambition and humanity, who was trapped in a half Km tall statue for her crimes against the pantheon until a group of adventurers could free her. The gods got together and decided this challenge would be a massive dungeon. 1 for each god.
Now... I've built interesting dungeons. But never a dungeon that is that long (20 in 1) and I'm running out of ideas.
The first god is Alihanna, godess of nature. Her "dungeon" is a pocket plane with skill challenges and some combats tied to her concept. Cool. The second god is Ragnar, the god of death (or slaughter). And here my problem starts.
Ragnar's Dungeon is supposed to be filled with his creation (goblins, hobgoblins, bugbears, orcs and ogres). It makes sense, because his goal is to kill the whole world, but it makes the dungeon a hack'n slash (except for the ocasional trap). If I make it too short, it doesn't feel like a challenge made by a god, but if it's too long... Well... A too long hack'n slash dungeon gets old real fast. So, I don't know how to make it interesting a dungeon that has as objective to kill the party.
The thing is: how to make a good, interesting, engaging Dungeon that exists to kill the players? It's not supposed to have much treasure except equipment from the creatures they kill (because the dungeon is a test and Ragnar doesn't care about gold) and it is supposed to have all those creatures and traps. Also, it should feel like a challenge from a god.