Исправил код

Assets/Group1/Scripts/EndScreen.cs

@@ -0,0 +1,25 @@
+using System;
+using System.Collections;
+using System.Collections.Generic;
+using UnityEngine;
+
+public class EndScreen : MonoBehaviour
+{
+    [SerializeField] private EnemiesList _enemiesList;
+    [SerializeField] private GameObject _endScreen;
+
+    private void OnEnable()
+    {
+        _enemiesList.EnemiesDied += OnEnemiesesDied;
+    }
+
+    private void OnDisable()
+    {
+        _enemiesList.EnemiesDied -= OnEnemiesesDied;
+    }
+
+    private void OnEnemiesesDied()
+    {
+        _endScreen.SetActive(true);
+    }
+}

Assets/Group1/Scripts/EnemyMovement.cs

@@ -0,0 +1,27 @@
+using System.Collections;
+using System.Collections.Generic;
+using UnityEngine;
+
+public class EnemyMovement : MonoBehaviour
+{
+    [SerializeField] private int _radiusModifier;
+    [SerializeField] private int _speed;
+    private Vector3 _target;
+
+    private void Start()
+    {
+        ChangeTargetPosition();
+    }
+
+    private void Update()
+    {
+        transform.position = Vector3.MoveTowards(transform.position, _target, _speed * Time.deltaTime);
+        if (transform.position == _target) 
+            ChangeTargetPosition();
+    }
+
+    private void ChangeTargetPosition()
+    {
+        _target = Random.insideUnitCircle * _radiusModifier;
+    }
+}

Packages/manifest.json

@@ -1,12 +1,21 @@
 {
   "dependencies": {
-    "com.unity.ads": "2.0.8",
-    "com.unity.analytics": "3.2.2",
-    "com.unity.collab-proxy": "1.2.15",
-    "com.unity.package-manager-ui": "2.0.7",
-    "com.unity.purchasing": "2.0.3",
-    "com.unity.textmeshpro": "1.3.0",
+    "com.unity.2d.sprite": "1.0.0",
+    "com.unity.2d.tilemap": "1.0.0",
+    "com.unity.ads": "3.5.2",
+    "com.unity.analytics": "3.5.3",
+    "com.unity.collab-proxy": "1.3.9",
+    "com.unity.ide.rider": "3.0.5",
+    "com.unity.ide.visualstudio": "2.0.7",
+    "com.unity.ide.vscode": "1.2.3",
+    "com.unity.purchasing": "3.0.1",
+    "com.unity.test-framework": "1.1.22",
+    "com.unity.textmeshpro": "3.0.4",
+    "com.unity.timeline": "1.5.2",
+    "com.unity.ugui": "1.0.0",
+    "com.unity.xr.legacyinputhelpers": "2.1.7",
     "com.unity.modules.ai": "1.0.0",
+    "com.unity.modules.androidjni": "1.0.0",
     "com.unity.modules.animation": "1.0.0",
     "com.unity.modules.assetbundle": "1.0.0",
     "com.unity.modules.audio": "1.0.0",

ProjectSettings/ProjectVersion.txt

@@ -1 +1,2 @@
-m_EditorVersion: 2018.3.14f1
+m_EditorVersion: 2021.1.0f1
+m_EditorVersionWithRevision: 2021.1.0f1 (61a549675243)