Dungeon Lords: Happy Anniversary includes the Dungeon Lords base game, the Festival Season expansion, stickers for food tokens, metal coins, a new "Dungeon Set-up" mini-expansion, and other items.

In Dungeon Lords, you are an evil dungeon lord who is trying to build the best dungeon out there. You hire monsters, build rooms, buy traps and defeat the do-gooders who wish to bring you down. Each turn, players use a hand of cards to choose where to place their worker imps. Actions vary from mining gold, hiring monsters, buying traps etc. Each action has three spots available - with each spot having different effects (e.g., mining gold lets you mine more gold in each spot). When using the cards, two cards will become locked and will not be able to be used next turn.

The entire game lasts two "game years", and each year consists of four seasons (a.k.a. turns). At the start of each season, players see the heroes and events to come in the following season, allowing them to prepare. At the end of each season after the first, heroes are allocated to each player according to the players' level of evilness. Heroes range from mighty heroes to sneaky thieves. Each hero has its own power for which the player needs to prepare for. At the end of each year, the heroes travel into the dungeons to fight.

Scoring in the game is based upon what you have built, the monsters you have hired and the heroes you have captured.

The Festival Season expansion adds a fifth season to the year: festival season. More time to build your dungeon, but also more time for adventurers to gather a larger party. There are new monsters, rooms, and traps to prepare your dungeon for the battle, but also new nasty spells for the adventurers and sneaky bards who encourage them to perform so-called "heroic" deeds – not to mention two paladins for each year, now ready to punish up to two evil players.

Would you like to push other players toward evil instead of moving yourself toward good when visiting the city? What about making an investment instead of traditional gold digging? Or what about repairing conquered tunnels or rooms instead of digging new ones? Only eight actions are still available to you, but each season one of those actions is replaced by an alternate set of spaces that offer new and intriguing options. And did we mention that it has recently become fashionable for dungeon lords to have their own personal pets?