added comments and organized project files

Assets/Scripts/Game/GameTimer.cs

@@ -0,0 +1,58 @@
+using TMPro;
+using UnityEngine;
+using UnityEngine.UI;
+
+public class GameTimer : MonoBehaviour
+{
+    public float startTime = 180f;
+    private float timeRemaining;
+    private bool timerRunning = false;
+
+    public Text timerText;
+    [SerializeField] private TextMeshProUGUI timer;
+
+    private void Start()
+    {
+        timeRemaining = startTime;
+        timer.text = "3:00.00";
+        UpdateTimerDisplay();
+    }
+
+    private void Update() // Updates the timer to show the time remaining
+    {
+        if (timerRunning)
+        {
+            timeRemaining -= Time.deltaTime;
+
+            if (timeRemaining <= 0)
+            {
+                timeRemaining = 0;
+                timerRunning = false;
+                OnTimerEnd();
+            }
+
+            UpdateTimerDisplay();
+        }
+    }
+
+    public void StartTimer() // Starts the timer
+    {
+        if (!timerRunning)
+        {
+            timeRemaining = startTime;
+            timerRunning = true;
+        }
+    }
+
+    private void UpdateTimerDisplay() // Formats and sets the time remaining
+    {
+        int minutes = Mathf.FloorToInt(timeRemaining / 60);
+        int seconds = Mathf.FloorToInt(timeRemaining % 60);
+        timer.text = string.Format("{0}:{1:D2}", minutes, seconds);
+    }
+
+    private void OnTimerEnd() // Ends the game when the time runs out
+    {
+        GameManager.Instance.GameOver();
+    }
+}