Minor bits:

- Consolidate FMOD closing code into a single method
- Added some experimental (commented-out) code to test running multiple instances of Quake
- Extra validation checks in FMOD music code
- Removed QuakeSpasm "feature" that skipped the demo reel at startup

Assets/Scripts/AudioManager.cs

@@ -54,22 +54,22 @@ public class AudioManager : MonoBehaviour
         result = fmodSystem.init(MaxChannels, FMOD.INITFLAGS.NORMAL, IntPtr.Zero);
         CheckFmodResult(result, "FMOD.System.init");
     }
+    
+    void OnDestroy()
+    {
+        CloseFmod();
+    }
 
     private void CheckFmodResult(FMOD.RESULT result, string cause)
     {
         if (result != FMOD.RESULT.OK)
         {
-            if (fmodSystem.hasHandle())
-            {
-                fmodSystem.close();
-                fmodSystem.release();
-                fmodSystem.clearHandle();
-            }
+            CloseFmod();
             throw new Exception($"[FMOD] Initialization failed : {cause} : {result.ToString()} : {FMOD.Error.String(result)}");
         }
     }
     
-    private void OnDestroy()
+    private void CloseFmod()
     {
         if (fmodSystem.hasHandle())
         {

Assets/Scripts/UniQuake.cs

@@ -169,6 +169,14 @@ public class UniQuake: MonoBehaviour
     private void LoadLibrary()
     {
         string dllFile = Path.Combine(Application.dataPath, DllPath);
+
+        // Experimental code to allow running multiple instances of Quake next to each other
+        // string dllName = Path.GetFileNameWithoutExtension(dllFile);
+        // string dllExt = Path.GetExtension(dllFile);
+        // string dllCopy = Path.Combine(Application.persistentDataPath, $"{dllName}{GetInstanceID()}{dllExt}");
+        // File.Copy(dllFile, dllCopy, true);
+        // dllFile = dllCopy;
+        
         libraryHandle = SystemLibrary.LoadLibrary(dllFile);
         if (libraryHandle == IntPtr.Zero)
         {

engine/Quake/bgmusic.c

@@ -141,6 +141,12 @@ static qboolean BGM_PlayStream(const char *filename)
 	FMOD_CREATESOUNDEXINFO exinfo;
 	FMOD_RESULT result;
 
+	if (!fmod_system || !bgm_channelGroup)
+	{
+		Con_Printf("FMOD System not initialized, cannot play BGM\n");
+		return false;
+	}
+
 	len = COM_FOpenFile(filename, &f, NULL);
 	fclose(f);
 	if (len < 1)

engine/Quake/host_cmd.c

@@ -2230,13 +2230,6 @@ void Host_Startdemos_f (void)
 	if (!sv.active && cls.demonum != -1 && !cls.demoplayback)
 	{
 		cls.demonum = 0;
-		if (!fitzmode)
-		{  /* QuakeSpasm customization: */
-			/* go straight to menu, no CL_NextDemo */
-			cls.demonum = -1;
-			Cbuf_InsertText("menu_main\n");
-			return;
-		}
 		CL_NextDemo ();
 	}
 	else