Missions are groups of separate tasks and goals in each Devil May Cry game that act as the story mode of the series. Like chapters in a book, they break up the action of the game into manageable sections organized around a specific theme or target. Missions are episodic in nature, and must be completed in ascending order to unlock the next mission. They are generally where all story progression occurs. Unlike additional content, missions contain cinematic sequences that expand the game by explaining character motivations, developing the plot, and illustrating the consequences of the characters' actions.
While on a mission, the player collects various Orbs, items, and weapons to strengthen the player's character. Missions often put the player's combat and puzzle-solving skills to the test through the use of puzzles, enemy encounters, environmental obstacles, sealed doors, and bosses. Certain missions also contain Secret Missions; small challenges much like side-quests that require the player to overcome certain conditions for a reward.
After completing a mission, a mission complete screen shows how well the player has performed on the mission. Using less time, becoming more stylish, and finding hidden Orbs scattered throughout the mission all affect the player's grade on the ranking screen. Additional criteria, such as taking no damage or using a Gold Orb during the mission, can also impact the player's grade. The player's total score is calculated based on the aforementioned criteria, then assigned a letter grade from D, the lowest, to S, the highest in the original series. In the reboot, SS and SSS are also possible to achieve, though this is only visible in Mission Rankings.
As the missions progresss, the character gets stronger though the various rewards granted to the player by overcoming the challenges set before him or her in the mission. Rewards include, but are not limited to; new Devil Arms, the Devil Trigger ability, Key Items, and new Styles.
After defeating all the missions on a difficulty mode, a new difficulty mode usually appears. The missions are the same, but these new difficulty modes are usually made harder by altering the strength and types of enemies encountered, and by making the ranking criteria stricter.
In the first game, the only way to replay a mission after completion is to start the game over. Additionally, once a game is started, there is no way to stop and restart the missions. All missions must be completed and the game must be defeated before the missions can be repeated. Devil May Cry 2 allowed the player to replay missions, but only after completing the game.
In later games, a mission select option was added so that, once the player has completed a mission, that mission may be replayed as many times as the player wants without penalty. Weapons, abilities, styles, and skills earned from later missions will remain unlocked for subsequent playthroughs, even if the player did not have access to any of those things for the first playthrough. Attempting a mission a second time is a great way to improve the player's score, as the player will have access to a wider range of skills than the first time, plus the player will waste less time exploring since he or she knows the paths and puzzle solutions.