Valhalla is not heaven. It is a hall — Odin's hall — and the einherjar, the warriors chosen from the battlefield by the Valkyries, are gathered there for a very specific purpose: to fight Ragnarok. They die well, they feast nightly on boar that regenerates, they drink mead from Heiðrún the goat, and every morning they rise and kill each other again in the fields outside, practicing for the last war. The old Norse afterlife is preparation, not rest.
The broader map is less tidy than late sources make it sound. Snorri Sturluson, writing in thirteenth-century Christian Iceland, schematized the sources into a neat geography — Odin's Valhalla for warriors, Freyja's Fólkvangr for half the battle-slain, Helheim under Niflheim for those who died of sickness or age, Rán's hall at the bottom of the sea for the drowned — but the Poetic Edda and the skaldic poetry underneath it are messier. The dead were often said simply to "go into the howe," the burial mound, where they remained present to the land and the family. Ancestor cults at the mound — offerings, conversation, prophetic consultation — were central to pre-Christian Scandinavian religion. The dead did not leave; they moved closer to the ground.
Hel the goddess (whose name became the English word) rules a hall that is gray and cold but not torture. Her realm is for those who did not die in glory. It is neither damnation nor reward; it is a fate. The ship-burials — the Oseberg ship, the Gokstad ship, the vessels laid down with their dead — suggest that even those not bound for Valhalla were believed to travel somewhere.
Ragnarok gives the whole system its horizon. The gods themselves die. Odin is swallowed by the wolf Fenrir; Thor kills the Midgard serpent and falls poisoned from its breath; Loki and Heimdall slay each other; the world burns in Surt's fire. But after the fire the land rises again, green, and two humans who sheltered inside Yggdrasil walk out to repopulate it. Baldr returns from Hel. The Norse cosmos is cyclical in a way Christian eschatology is not: endings are also beginnings, and even the gods are subject to time.
What makes the tradition distinctive is how un-transcendent it is. The Norse dead do not escape matter. They feast, they fight, they sit on burial mounds, they travel in ships. The afterlife continues the texture of this life, and what a warrior wanted from it was not peace but the chance to die again beside his comrades at the end of the world.