We will work on two classes: the enemy generator containing the evolutionary algorithm and the enemy controller for handling the real-time instances from the enemy templates created in the previous section. We'll also use some game logic.

We need to define the controller for such a template with EvolEnemyController:

1. Create the class named EvolEnemyController:

using UnityEngine;
using System;
using System.Collections;

public class EvolEnemyController :
    MonoBehaviour, IComparable<EvolEnemyController>
{
  // next steps  
}

2. Define its member variables:

public static int counter = 0;
[HideInInspector]
public EvolEnemy template;
public float time;
protected Vector2 bounds;
protected SpriteRenderer _renderer;
protected BoxCollider2D _collider;

3. Implement the member function from the IComparable interface:

public int CompareTo(EvolEnemyController other)
{
  return other.time > time ? 0 : 1;
}

4. Implement the initialization function:

public void Init(EvolEnemy template, Vector2 bounds)
{
  this.template = template;
  this.bounds = bounds;
  Revive();
}

5. Implement the function for reactivating the object:

public void Revive()
{
  gameObject.SetActive(true);
  counter++;
  gameObject.name = "EvolEnemy" + counter;

  Vector3 newPosition = UnityEngine.Random.insideUnitCircle;
  newPosition *= bounds;
  _renderer.sprite = template.sprite;
  _collider = gameObject.AddComponent<BoxCollider2D>();
}

6. Implement the Update function:

private void Update()
{
  if (template == null)
    return;
  time += Time.deltaTime;  
}

7. Implement the function for defeating the enemy with a click:

private void OnMouseDown()
{
 Destroy(_collider);
 gameObject.SendMessageUpwards("KillEnemy", this);
}

Finally, we work on the enemy generator:

1. Create a new class named EvolEnemyGenerator:

using UnityEngine;
using System.Collections.Generic;

public class EvolEnemyGenerator : MonoBehaviour
{
  // next
}

2. Declare all the necessary member variables:

public int mu;
public int lambda;
public int generations;
public GameObject prefab;
public Vector2 prefabBounds;
protected int gen;
private int total;
private int numAlive;
public EvolEnemy[] enemyList;
private List<EvolEnemyController> population;

3. Implement the Start member function:

private void Start()
{
  Init();
}

4. Declare the initialization function:

public void Init()
{
  // next steps
}

5. Declare its internal variables:

gen = 0;
total = mu + lambda;
population = new List<EvolEnemyController>();
int i, x;
bool isRandom = total != enemyList.Length;

6. Create the initial generation or wave of enemies:

for (i = 0; i < enemyList.Length; i++)
{
  EvolEnemyController enemy;
  enemy = Instantiate(prefab).GetComponent<EvolEnemyController>();
  enemy.transform.parent = transform;
  EvolEnemy template;
  x = i;
  if (isRandom)
    x = Random.Range(0, enemyList.Length - 1);
  template = enemyList[x];
  enemy.Init(template, prefabBounds);
  population.Add(enemy);
}

7. Initialize the number of enemies alive relative to the size of population:

numAlive = population.Count;

8. Define the function for creating a new generation:

public void CreateGeneration()
{
  // next steps
}

9. Check whether the number of generations created is greater than allowed:

if (gen > generations)
  return;

10. Sort the individuals in ascending order, and create a list of surviving individuals:

population.Sort();
List<EvolEnemy> templateList = new List<EvolEnemy>();
int i, x;
for (i = mu; i < population.Count; i++)
{
  EvolEnemy template = population[i].template;
  templateList.Add(template);
  population[i].Revive();
}

11. Create new individuals from the surviving types:

bool isRandom = templateList.Count != mu;
for (i = 0; i < mu; i++)
{
  x = i;
  if (isRandom)
    x = Random.Range(0, templateList.Count - 1);
  population[i].template = templateList[x];
  population[i].Revive();
}

12. Increase the number of generations, and reset the number of individuals alive:

gen++;
numAlive = population.Count;

13. Implement the function for defeating enemies:

public void KillEnemy(EvolEnemyController enemy)
{
  enemy.gameObject.SetActive(false);
  numAlive--;
  if (numAlive > 0)
    return;
  Invoke("CreateGeneration", 3f);
}