Big Bad Overlord is a card and dice game for 3-6 people in which players assume the roles of evil Dukes vying to take over the world. Players gather minions great and small, ranging from Riff-Raff to Horrible Monsters, battle each other, and fend off attacks by occasional do-gooders (such as adventuring bands and small children). The game takes about an hour to play.
The goal is to eliminate all other players and become the Big Bad Overlord. Players start with six cards, half of which they can keep face-down. The face-up cards serve as the players' armies and can be used to attack other players. Each turn, players draw a new card and add it to their army. (Unless they draw a do-gooder, in which case the player has to fight it off!) There are three combat abilities - Mind control, Magic, and Melee. Most cards have at least one ability, and some have more. A successful Mind-control attack allows you to capture an enemy card; magic blows things up (especially cards weak against magic, such as the otherwise powerful Machines-O-Death); and melee allows you to chop things up.
Players fight each other using all available attacks, rolling 2 six-sided dice to determine the winner of each battle. Die rolls are modified according to the relative attack and defense strengths of each side's army in each combat category. But even the most lopsided of battles isn't in vain - a natural 12 always wins, no matter what the modifiers, and a natural 2 always fails.
In addition to the evil minions and do-gooders, the deck contains two magical artifacts. They're important because players need them to survive the endgame. When all the cards are drawn from the deck, only players who have an artifact survive. At that point, if two players are still in the game, there's a final battle in which the evil Dukes use the artifacts to smash each other's troops.
Players can gang up on each other, help each other defend against attack, backstab each other, and more. Defeat your foes, play them against each other, hoard a precious artifact or obtain one at all costs - Big Bad Overlord is a game where it's good to be bad.