Im making a spawner need help!!

So im making a simple game that has a spawner. here is my script. and the problem is that everytime the game runs it spawns the same enemy but i need it to spawn different enemies.
the other problem is that everytime 2 enemies spawn it reloads the game. i need helpp

Code (csharp):

1.  
2. using System.Collections;
3. using System.Collections.Generic;
4. using UnityEngine;
5.  
6. public class Spaawner : MonoBehaviour
7. {
8.     public float startTimeBtwSpawn;
9.     private float timeBtwSpawn;
10.     public GameObject[] enemies;
11.  
12.     private void Update()
13.     {
14.         if (timeBtwSpawn <= 0) {
15.             int rand = Random.Range(0, enemies.Length);
16.             Instantiate(enemies[rand], transform.position,  Quaternion.identity);
17.             timeBtwSpawn = startTimeBtwSpawn;
18.         }else {
19.             timeBtwSpawn -= Time.deltaTime;
20.         }
21.     }
22. }
23.  
24.  

and this is my enemy script

Code (csharp):

1.  
2. using System.Collections;
3. using System.Collections.Generic;
4. using UnityEngine;
5. using UnityEngine.SceneManagement;
6.  
7. public class Enemy : MonoBehaviour
8. {
9.     public float speed;
10.  
11.     private void Update()
12.     {
13.         transform.Translate(Vector2.left * speed * Time.deltaTime);
14.     }
15.  
16.     void OnTriggerEnter2D(Collider2D other)
17.     {  
18.  
19.         if (other.CompareTag("Player")) {
20.             SceneManager.LoadScene(SceneManager.GetActiveScene().buildIndex);
21.         }
22.  
23.         if (other.tag == gameObject.tag)
24.         {
25.             Destroy(other.gameObject);
26.             Destroy(gameObject);
27.         }else
28.         {
29.             SceneManager.LoadScene(SceneManager.GetActiveScene().buildIndex);
30.         }
31.     }
32. }
33.  
34.  

 

Use

Code (CSharp):

1. Debug.Log ( "My message" ) ;

To track errors and issues.

What is the length of enemies.Length?

In the second script, you reload scene, when either triggered object has Player tag, or no matching tag at all.
So if second object is spawned, and collides with first, I presume it compares tag with each other. As the result, reloading a scene.

 

The problem is that when an enemy that isnt a circle spawns it reloads the scene and my three enemies are circle square and triangle

 

Sorry, I have no idea, what you mean by "circle spawn".
Perhaps screenshot / drawing of the situation will be of any help?
Still, please follow my initial suggestions and respond to questions I asked. Otherwise is difficult to even narrow the problem down.

 

im talking about my enemies ones a square, ones a triangle, and ones a circle,
when an enemy that isnt a circle spawns it destroys them or reloads the scene

 

I understand that there are 3 enemies circle, triangle and square. Like Antypodish pointed out there are two occasions when the scene gets reloaded: 1. When enemy collides with a Gameobject tagged as Player. 2. When enemy collides with a Gameobject which isn't tagged as enemy or isn't tagged at all. I suggest deleting that ELSE statement, since the scene should probably get reloaded only when the player gets hit.
Also when all of your enemies have the enemy script, then you don't need Destroy(other.gameobject) under the enemy tag comparison statement. So make sure your enemies and player are tagged correctly.
The enemies that spawn should be random, but this also means that one may get spawned many times in a row. Make sure your array is filled up correctly in the inspector and that there are all the different enemy prefabs you want to spawn.

 

the square and triangle stay back but the cricle moves forward thats the problem not that the enemies collide with eachother and also i need the else statement

 

Do you have enemies script attached to the square and triangle enemies?