fix multiple issues

Assets/Scripts/CannonAreaEffect.cs

@@ -9,16 +9,29 @@ public class CannonAreaEffect : MonoBehaviour
     int damagePerSecond;
     float slowMultiplier = 1f;
     float expiresAt;
+    SpriteRenderer visual;
 
-    public void Configure(float effectDuration, int burnDamagePerSecond, float craterSlowMultiplier)
+    public void Configure(float effectDuration, int burnDamagePerSecond, float craterSlowMultiplier, float radius)
     {
         duration = effectDuration;
         damagePerSecond = burnDamagePerSecond;
         slowMultiplier = Mathf.Clamp(craterSlowMultiplier, 0.1f, 1f);
         expiresAt = Time.time + duration;
+        CreateVisual(radius);
         Destroy(gameObject, duration);
     }
 
+    void Update()
+    {
+        if (visual == null || duration <= 0f)
+            return;
+
+        float remaining = Mathf.Clamp01((expiresAt - Time.time) / duration);
+        Color color = visual.color;
+        color.a = Mathf.Lerp(0f, color.a, remaining);
+        visual.color = color;
+    }
+
     void OnTriggerStay2D(Collider2D other)
     {
         if (!other.CompareTag("Enemy"))
@@ -44,4 +57,44 @@ public class CannonAreaEffect : MonoBehaviour
         health.TakeDamage(Mathf.Max(1, damagePerSecond));
         nextDamageTick[health] = Time.time + 1f;
     }
+
+    void CreateVisual(float radius)
+    {
+        GameObject visualObject = new GameObject("Visual", typeof(SpriteRenderer));
+        visualObject.transform.SetParent(transform, false);
+        visualObject.transform.localScale = Vector3.one * radius * 2f;
+
+        visual = visualObject.GetComponent<SpriteRenderer>();
+        visual.sprite = CreateCircleSprite();
+        visual.sortingOrder = -1;
+
+        if (damagePerSecond > 0 && slowMultiplier < 1f)
+            visual.color = new Color(0.95f, 0.33f, 0.12f, 0.34f);
+        else if (damagePerSecond > 0)
+            visual.color = new Color(1f, 0.32f, 0.08f, 0.34f);
+        else
+            visual.color = new Color(0.34f, 0.24f, 0.16f, 0.38f);
+    }
+
+    static Sprite CreateCircleSprite()
+    {
+        const int size = 64;
+        Texture2D texture = new Texture2D(size, size, TextureFormat.RGBA32, false);
+        texture.filterMode = FilterMode.Bilinear;
+        Vector2 center = new Vector2((size - 1) * 0.5f, (size - 1) * 0.5f);
+        float radius = size * 0.46f;
+
+        for (int y = 0; y < size; y++)
+        {
+            for (int x = 0; x < size; x++)
+            {
+                float distance = Vector2.Distance(new Vector2(x, y), center);
+                float alpha = Mathf.Clamp01((radius - distance) / 5f);
+                texture.SetPixel(x, y, new Color(1f, 1f, 1f, alpha));
+            }
+        }
+
+        texture.Apply();
+        return Sprite.Create(texture, new Rect(0f, 0f, size, size), new Vector2(0.5f, 0.5f), size);
+    }
 }