Added basic enemy

Does not attack the player currently

Assets/Scripts/EnemyController.cs

@@ -0,0 +1,9 @@
+using UnityEngine;
+
+public class EnemyController : OrbitalPositionBehaviour
+{
+    public override void OnStart()
+    {
+        m_OrbitalPosition.m_DeletedAtCentre = true;
+    }
+}

Assets/Scripts/EnemyController.cs.meta

@@ -0,0 +1,11 @@
+fileFormatVersion: 2
+guid: 8a4502a12b7f15246aa7b9cc2d30a862
+MonoImporter:
+  externalObjects: {}
+  serializedVersion: 2
+  defaultReferences: []
+  executionOrder: 0
+  icon: {instanceID: 0}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 

Assets/Scripts/OrbitalPosition.cs

@@ -10,6 +10,9 @@ public class OrbitalPosition
 
     public Transform owner = null;
 
+    public int m_SpinSpeed = 1;
+    public bool m_DeletedAtCentre = false;
+
     public OrbitalPosition(GameObject _owner)
     {
         pRing = GlobalOrbitalPositionManager.LastRingID;
@@ -126,7 +129,15 @@ public class GlobalOrbitalPositionManager : MonoBehaviour
         foreach (OrbitalPosition orbitalPosition in m_ObjectInstances)
         {
             if (!m_Distances.ContainsKey(orbitalPosition.pRing))
+            {
+                if (orbitalPosition.m_DeletedAtCentre)
+                {
+                    Destroy(orbitalPosition.owner.gameObject);
+                    continue;
+                }
+
                 orbitalPosition.pRing = m_LastGeneratedRing;
+            }
 
             float distance = m_Distances[orbitalPosition.pRing];
             orbitalPosition.DistanceFromCentre = distance;
@@ -158,5 +169,5 @@ public abstract class OrbitalPositionBehaviour : MonoBehaviour
     private void OnDestroy() =>
         GlobalOrbitalPositionManager.UnregisterOrbitalPositionInstance(m_OrbitalPosition);
 
-    public abstract void OnStart();
+    public virtual void OnStart() { }
 }

Assets/Scripts/PlayerController.cs

@@ -1,11 +1,9 @@
-using System.Collections;
-using System.Collections.Generic;
-using UnityEditor;
 using UnityEngine;
 
 public class PlayerController : OrbitalPositionBehaviour
 {
     float m_StartPosition;
+    public GameObject m_EnemyPrefab;
 
     public override void OnStart()
     {
@@ -18,5 +16,10 @@ public class PlayerController : OrbitalPositionBehaviour
         {
             m_OrbitalPosition.pRing += 1;
         }
+
+        if (Input.GetKey(KeyCode.E))
+        {
+            Instantiate(m_EnemyPrefab);
+        }
     }
 }