When you first dive into Championship Edition DX, only the standard Championship II course is unlocked, but each round you play usually unlocks a new maze or mode. Each maze also has many game options such as Score Attack, Time Trials, and Ghost Combos (see how many ghosts you can eat with one Power Pellet). Dungeon, on the other hand, has long, cramped corridors. For example, Spiral has several coils that are easy to get trapped in. DX has nine mazes, most of which are new creations that offer a lot of variety. While the first Championship Edition was super fun, there were only a couple of mazes and modes. This is also a key technique in getting those high scores.
Finally grabbing that Power Pellet and devouring a hundred ghosts in a row is one of the most satisfying things I've done in a game this year. Hold off on eating a Power Pellet long enough and you may find a hundred ghosts trailing behind you in a long conga line. You'll see the spirits sleeping around a maze, and as Pac-Man whizzes by they'll wake up and give chase. Pac-Man now has many more ghosts to contend with.