Square Enix confirmed Crisis Core: FFVII Reunion will feature a total of 300 SOLDIER Missions for Zack to complete. Aside from physical rewards such as Materia, you can also use these missions to increase how many accessories you can equip. These missions have difficulty ranks and will unlock as you play through the story.
Based on the screenshot, we can see that some Crisis Core: FFVII missions will have multiple parts. M1-3 are missions from the weapons development team. M1-3-2 will have Zack help out the development team in testing out new weapons made specifically to counter Shinra weapons. This is because Genesis took a bunch of them and used them to attack Shinra.
You can get special rewards depending on how many missions you finish. M1-3-2 will grant Zack the Cura Materia. Meanwhile, completing 5% of all the missions in the game will give him Thunder.
Crisis Core: FFVII Reunion is an action RPG that serves as a remake of the original PSP game, Crisis Core: FFVII. The story is a prequel to Final Fantasy VII and will put players in the shoes of Zack Fair. According to past interviews with Square Enix, Crisis Core: FFVII Renion will be closer to a remastered version of the original, as it will faithfully recreate the story and core elements.
Crisis Core: FFVII Reunion will come out on the PS4, PS5, Nintendo Switch, Xbox One, Xbox Series X, and Windows PC on December 13, 2022.