Unity 2D - Why can not the enemy made? - unity3d

Question

I am making a running game, but I face the big problem.
In the stage, Obstacles are created. But After some time, unity didn't make new Obstacle. Why does this happen?
public class GameManager : MonoBehaviour {
public float waitingTime = 1.5f;
public static GameManager manager;
public bool ready = true;
public GameObject cactus;
float time = 0;
// Use this for initialization
void Start () {
manager = this;
}
// Update is called once per frame
void Update () {
time += Time.deltaTime;
//Debug.Log(time);
if(time>2f && ready==true)
{
ready = false;
time = 0;
InvokeRepeating("MakeCactus", 1f, waitingTime);
}
}
void MakeCactus()
{
Instantiate(cactus);
}
public void GameOver()
{
//CancelInvoke("MakeCactus");
iTween.ShakePosition(Camera.main.gameObject, iTween.Hash("x", 0.2, "y", 0.2, "time", 0.5f));
}
}

Answer 1

You don't need Update method at all. As you are using it just to delay your spawning. Your code can be re-written like this:
public class GameManager : MonoBehaviour
{
public float waitingTime = 1.5f;
public static GameManager manager;
public GameObject cactus;
void Awake()
{
manager = this;
InvokeRepeating("MakeCactus", 3f, waitingTime);
}
void MakeCactus()
{
Instantiate(cactus);
}
public void GameOver()
{
//CancelInvoke("MakeCactus");
iTween.ShakePosition(Camera.main.gameObject, iTween.Hash("x", 0.2, "y", 0.2, "time", 0.5f));
}
}
Hopefully this will solve the problem