diff --git a/Assets/Scripts/LevelConfig/WaveConfig.cs b/Assets/Scripts/LevelConfig/WaveConfig.cs
index 960f433..e4bc275 100644
--- a/Assets/Scripts/LevelConfig/WaveConfig.cs
+++ b/Assets/Scripts/LevelConfig/WaveConfig.cs
@@ -9,6 +9,8 @@ public class WaveConfig : ScriptableObject
     private List<EnemyType> _constantSpawn = new List<EnemyType>();
     [SerializeField]
     private float _gameDuration = 0;
+    private float _enemySpawndOnStart = 0;
+    private int _enemySum = 0;
     public List<EnemyType> ConstantSpawn
     {
         get
@@ -18,7 +20,13 @@ public class WaveConfig : ScriptableObject
     }
     public float GetInterval()
     {
-        float interval = SumCount().ToFloat() / _gameDuration * 0.01f;
+        float interval = _gameDuration * 60.0f / (_enemySum > 0 ? _enemySum.ToFloat() : SumCount()) ;
+        return interval;
+    }
+    public float GetUpdatedInterval()
+    {
+        _enemySpawndOnStart++;
+        float interval = Mathf.Max(_gameDuration * 60.0f / (_enemySum - _enemySpawndOnStart).ToFloat(), 0);
         return interval;
     }
     public EnemyType GetRandomSpawn()
@@ -29,15 +37,13 @@ public class WaveConfig : ScriptableObject
         }
         return _constantSpawn[Random.Range(0, _constantSpawn.Count - 1)];
     }
-
-    private int SumCount()
+    private float SumCount()
     {
-        int sum = 0;
         foreach (EnemyType enemy in _constantSpawn)
         {
-            sum += enemy.Count;
+            _enemySum += enemy.Count;
         }
-        return sum;
+        return _enemySum.ToFloat();
     }
 
 }
diff --git a/Assets/Scripts/LevelConfig/WaveObserver.cs b/Assets/Scripts/LevelConfig/WaveObserver.cs
index fced3ae..04eda44 100644
--- a/Assets/Scripts/LevelConfig/WaveObserver.cs
+++ b/Assets/Scripts/LevelConfig/WaveObserver.cs
@@ -4,40 +4,44 @@ using UnityEngine;
 public class WaveObserver : Singleton<WaveObserver>
 {
     private List<SpawnerTile> _subjects = new List<SpawnerTile>();
-    private List<int> _aliveEnemyCount = new List<int>();
+    private List<float> _aliveEnemyCount = new List<float>();
     private List<int> _copyConstantSpawn;
     private WaveConfig _levelConfig;
-    private const int MAXENEMYCOUNT = 3;
-    public WaveConfig LevelConfig 
-    { 
-        set 
-        { 
+    private const int MAXTOUGHNESS = 10;
+    private int _spawnerTiming = 0;
+    public WaveConfig LevelConfig
+    {
+        set
+        {
             _levelConfig = value;
             _copyConstantSpawn = new List<int>();
             foreach (EnemyType enemy in _levelConfig.ConstantSpawn)
             {
                 _copyConstantSpawn.Add(enemy.Count);
             }
-        } 
+        }
     }
-    
+
     public void Attach(SpawnerTile spawnerSubject)
     {
+
         spawnerSubject.Prefab = _levelConfig.GetRandomSpawn().GetEnemyObject();
-        spawnerSubject.InitialSpawnSpeed(_levelConfig.GetInterval());
+        spawnerSubject.ChangeSpawnSpeed(_levelConfig.GetInterval() * ++_spawnerTiming);
         _subjects.Add(spawnerSubject);
         _aliveEnemyCount.Add(0);
+        Debug.Log("Je suis le " + _spawnerTiming + "e a agir!!!");
     }
 
     public void NotifySpawned(SpawnerTile spawnerSubject)
     {
         GameObject paramPrefab = spawnerSubject.Prefab;
+        spawnerSubject.ChangeSpawnSpeed(_levelConfig.GetInterval() * _spawnerTiming);
         if (paramPrefab.Equals(_levelConfig.ConstantSpawn[0].GetEnemyObject()))
         {
             int currentCount = 0;
             for (int i = 0; i < _copyConstantSpawn.Count; i++)
             {
-                if(_levelConfig.ConstantSpawn[i].GetEnemyObject() == paramPrefab)
+                if (_levelConfig.ConstantSpawn[i].GetEnemyObject() == paramPrefab)
                 {
                     currentCount = _copyConstantSpawn[i]--;
                     break;
@@ -56,29 +60,49 @@ public class WaveObserver : Singleton<WaveObserver>
         }
     }
 
-    public int NotifyEnemy(float yPosition)
+    public int NotifyEnemy(float yPosition, float toughness)
+    {
+        int index = FindEnemyIndex(yPosition);
+        _aliveEnemyCount[index] += toughness;
+        if (_aliveEnemyCount[index] >= MAXTOUGHNESS)
+        {
+            _subjects[index].StopSpawn();
+        }
+        return index;
+    }
+
+    public void NotifyDies(int position, float toughness)
+    {
+        _aliveEnemyCount[position] -= toughness;
+        if (_aliveEnemyCount[position] < MAXTOUGHNESS)
+        {
+            _subjects[position].StartSpawn();
+        }
+        Debug.Log("Fallen monster ");
+    }
+
+    /**
+     * Called when an enemy is spawned automatically at the start of the game
+     * Adjusts the intervall between spawns
+     */
+    public void NotifyOnStart()
+    {
+        float interval = _levelConfig.GetUpdatedInterval();
+        foreach (var subject in _subjects)
+        {
+            subject.ChangeSpawnSpeed(interval);
+        }
+    }
+
+    private int FindEnemyIndex(float yPosition)
     {
         for (int i = 0; i < _subjects.Count; i++)
         {
-            if(_subjects[i].Position.y == yPosition)
+            if (_subjects[i].Position.y == yPosition)
             {
-                _aliveEnemyCount[i]++;
-                if(_aliveEnemyCount[i] >= MAXENEMYCOUNT)
-                {
-                    _subjects[i].StopSpawn();
-                }
                 return i;
             }
         }
         return -1;
     }
-
-    public void NotifyDies(int position)
-    {
-        if(_aliveEnemyCount[position] >= MAXENEMYCOUNT)
-        {
-            _subjects[position].StartSpawn();
-        }
-        _aliveEnemyCount[position]--;
-    }
 }
diff --git a/Assets/Scripts/Opponent/Opponent.cs b/Assets/Scripts/Opponent/Opponent.cs
index 25de0fd..e8b686e 100644
--- a/Assets/Scripts/Opponent/Opponent.cs
+++ b/Assets/Scripts/Opponent/Opponent.cs
@@ -8,7 +8,8 @@ public class Opponent : Entity
     private Vector2 _movementVector = Vector2.zero;
     private Rigidbody2D _rigidbody;
     private WaveObserver _observer;
-    private int _index;
+    private int _observerIndex;
+    private float _toughness;
 
     public override void Start()
     {
@@ -17,7 +18,8 @@ public class Opponent : Entity
         _rigidbody = GetComponent<Rigidbody2D>();
         Animation = gameObject.AddComponent<AnimationEntity>();
         _observer = WaveObserver.Instance;
-        _index = _observer.NotifyEnemy(transform.position.y);
+        _toughness = Mathf.Round((base.Hp / 10) / 2);
+        _observerIndex = _observer.NotifyEnemy(transform.position.y, _toughness);
     }
 
     void Update() 
@@ -52,7 +54,7 @@ public class Opponent : Entity
 
     private void OnDisable()
     {
-        _observer.NotifyDies(_index);
+        _observer.NotifyDies(_observerIndex, _toughness);
     }
 
 }
diff --git a/Assets/Scripts/Tiles/SpawnerTile.cs b/Assets/Scripts/Tiles/SpawnerTile.cs
index e12f99c..e79be65 100644
--- a/Assets/Scripts/Tiles/SpawnerTile.cs
+++ b/Assets/Scripts/Tiles/SpawnerTile.cs
@@ -14,9 +14,6 @@ public class SpawnerTile : LevelTile
     [SerializeField, Range(0, 1.001f)]
     private float _spawnCounter = 0;
     private WaveObserver _observer;
-    private float _initialSpawnSpeed;
-    private const float MAX_SPAWN_SPEED = 0.01f;
-    private const float RANDOM_MODIFIER = 5.0f;
     private bool stopped = false;
 
 
@@ -27,6 +24,7 @@ public class SpawnerTile : LevelTile
         if (_spawnOnStart && _lifetime <= 0)
         {
             _prefab.Create(Position, parent: LevelManager.Instance.LevelTransform);
+            _observer.NotifyOnStart();
         }
     }
 
@@ -35,13 +33,12 @@ public class SpawnerTile : LevelTile
         _lifetime += Time.deltaTime;
         if (!stopped)
         {
-            _spawnCounter += Time.deltaTime * _spawnSpeed;
+            _spawnCounter += Time.deltaTime;
         }
-        if (_spawnCounter < 1) return;
+        if (_spawnCounter < _spawnSpeed) return;
 
         _spawnCounter = 0;
         _prefab.Create(Position, parent: LevelManager.Instance.LevelTransform);
-        _spawnSpeed = Mathf.Max(_initialSpawnSpeed / Random.Range(1.0f, RANDOM_MODIFIER), MAX_SPAWN_SPEED);
         _observer.NotifySpawned(this);
     }
     public override bool Equals(ILevelObject other)
@@ -98,9 +95,8 @@ public class SpawnerTile : LevelTile
         }
     }
 
-    public void InitialSpawnSpeed(float value)
+    public void ChangeSpawnSpeed(float value)
     {
-        _initialSpawnSpeed = value;
-        _spawnSpeed = Mathf.Max(_initialSpawnSpeed / Random.Range(1.0f, RANDOM_MODIFIER - 2.0f), MAX_SPAWN_SPEED);
+        _spawnSpeed = value;
     }
 }
\ No newline at end of file