In Gloom, from Atlas Games, you take control of a family of miserable people and make them more miserable, trying to become the most miserable family of all before you kill your family off.
The world of Munchkin, by contrast, contains plenty of happy people. Warriors who slay monsters, adventurers who grab loot, heroes who level up. Heck, halflings who stay at home eating pie all day. But the world of Munchkin is also sad and benighted, a place where those very same Munchkins are all too often backstabbed by buddies, dined on by dragons, and discovered by doom ducks. Heroes delve too deep, plummet down pits, and lose their loot — and that's before they die.