I am using Unity to develop my game, and I want to know how to save the formation of the enemy in a STG game, You know that in a STG game, there can be many kinds of formation of enemy. I decide to use enum to create the enum formationkind of the enemy and use the formationkind to decide the moving of the enemy, but first of all, I need to save each of the position of the enemy in the formation, can I use the Vector3[][] to save them?

For example Vector3[][] temp; temp[0][1] means the second enemy's position in the first kind of formation.

This can be accomplished by creating an Object array. Each object has an instance of an enemy, and the location it in in the world.

Example:

// Example of a class that can be saved and iterated from an array
// Written in Java

public class EnemyListExample{

Enemy e;
Group g;
int x;
int y;

     public EnemyListExample(Enemy enemy, Group, group, int X_Loc, int Y_Loc){
          e = enemy;
          g = group;
          x = X_Loc;
          y = Y_Loc
     }
     public Enemy getEnemy(){ return e; }
     public Group getGroup(){ return g; }
     public int getX_Loc(){ return x; }
     public int getY_Loc(){ return y; }
     
}

Code Fox has the right idea. If you only want to save the positions of the enemies, a list of vector3's will do. However, that could get a little bit nasty when you need to work on a per-enemy basis. Ideally, you want to create a list of gameobject's. On save, you can then add the enemy game objects to the list. This way, you will have the reference to the enemies, as well as the transform (position) for each.

EDIT: Just realized that you may or may not be using C# with Unity. In my above post I assume you are using C#. Regardless, the idea is the same for any of Unity's languages.

Is it good that I create all the enemies in one stage, and set the positions of them in the scene, when the player has arrived some place, I let the enemy in the view begin to move in a special formation? Is most of the STG game designed in this way? I think that the enemy in each stage is not random.