Missions are the biggest source of exp and provide most of the storyline in GhostX and is one of the unique features of the game.
The missions are unlocked free through quests and gaining levels. Although the first mission is given at the start of the game after the Prologue mission, Mission 2 and beyond are unlocked by gaining levels. Each Mission contains a set amount of quests you need to complete which get increasingly more difficult each time. The monsters in missions are generally tougher than those found in the areas where a mission takes place, often containing even more areas then the normal levels.
When playing a mission you can increase your mission score by doing lots of Combos and killing many enemies, as well as finishing the mission quickly and without dying. The Score you gain will decide what Rank you get on the Mission's Rank List, which appears at the end of the mission and shows you the top ten scores and your score. Although only the top 10 are shown, individual ranks can go as far as 1000; if you're below rank 1000, your rank will be displayed as 1001.
Together, your Time, Mission score, and Deaths will decide if you are awarded a Perfect Clear for a Mission, which means you will gain a new title, or possibly a rare item!
Quests that have the name ending
(Mission Quest) take place inside a mission, usually in last mission you have access to.