Dungeon Crawler games are getting a greater prominent rise in attention in the present day. Therefore, managing the pace in dungeon games is necessary. In this paper, we generate dungeon levels with the game pacing as intended by the game designer by integrating the concept of the Mission and Space framework and Game Design Patterns to generate dungeon game levels with the intended pacing. The Mission and Space framework handles the generation of tasks and in-game geometry spaces. We also present Pacing Patterns as patterns of the pacing on a game level to drive the level generations. We use a genetic algorithm to generate the potential level candidates. Those processes are encapsulated in a mixed-initiative tool, Pacing-based Dungeon Generator, to generate meaningful dungeon levels for players based on game designer preferences of game pacing. The proposed approach can minimize both time and expenses used to create game levels and effectively provide a more formal approach for game designers. Moreover, it keeps the players’ progression and experience as what the designer expected.