The mission-based campaign sports plenty of mindless stages that one can generally blitz through in less than three minutes, and none of its bosses require any particular ingenuity to clear. However, some of the puzzles actually take a bit of exploration or trial-and-error to crack. When the level's gimmick removes or limits your options, you're often strapped in for a tedious ride — but several missions require you to gain ground by taking advantage of a weapon's unique characteristics, and these "eureka" moments feel more rewarding to reach.