diff --git a/src/d_clisrv.c b/src/d_clisrv.c
index 72f60aa9f..10a5c1367 100644
--- a/src/d_clisrv.c
+++ b/src/d_clisrv.c
@@ -4463,6 +4463,7 @@ static void Local_Maketic(INT32 realtics)
 void SV_SpawnPlayer(INT32 playernum, INT32 x, INT32 y, angle_t angle)
 {
 	tic_t tic;
+	UINT8 numadjust = 0;
 
 	(void)x;
 	(void)y;
@@ -4472,7 +4473,21 @@ void SV_SpawnPlayer(INT32 playernum, INT32 x, INT32 y, angle_t angle)
 	// spawning, but will be applied afterwards.
 
 	for (tic = server ? maketic : (neededtic - 1); tic >= gametic; tic--)
+	{
+		if (numadjust++ == BACKUPTICS)
+		{
+			DEBFILE(va("SV_SpawnPlayer: All netcmds for player %d adjusted!\n", playernum));
+			// We already adjusted them all, waste of time doing the same thing over and over
+			// This shouldn't happen normally though, either gametic was 0 (which is handled now anyway)
+			// or maketic >= gametic + BACKUPTICS
+			// -- Monster Iestyn 16/01/18
+			break;
+		}
 		netcmds[tic%BACKUPTICS][playernum].angleturn = (INT16)((angle>>16) | TICCMD_RECEIVED);
+
+		if (!tic) // failsafe for gametic == 0 -- Monster Iestyn 16/01/18
+			break;
+	}
 }
 
 // create missed tic
diff --git a/src/d_netcmd.c b/src/d_netcmd.c
index b1e3bc9d2..6f0406a21 100644
--- a/src/d_netcmd.c
+++ b/src/d_netcmd.c
@@ -1535,7 +1535,12 @@ static void Command_Playdemo_f(void)
 
 	CONS_Printf(M_GetText("Playing back demo '%s'.\n"), name);
 
-	G_DoPlayDemo(name);
+	// Internal if no extension, external if one exists
+	// If external, convert the file name to a path in SRB2's home directory
+	if (FIL_CheckExtension(name))
+		G_DoPlayDemo(va("%s"PATHSEP"%s", srb2home, name));
+	else
+		G_DoPlayDemo(name);
 }
 
 static void Command_Timedemo_f(void)
diff --git a/src/lua_script.c b/src/lua_script.c
index 853ed5a2f..fdaa12c78 100644
--- a/src/lua_script.c
+++ b/src/lua_script.c
@@ -854,11 +854,19 @@ static void ArchiveTables(void)
 		lua_pushnil(gL);
 		while (lua_next(gL, -2))
 		{
-			ArchiveValue(TABLESINDEX, -2); // key should be either a number or a string, ArchiveValue can handle this.
+			// Write key
+			e = ArchiveValue(TABLESINDEX, -2); // key should be either a number or a string, ArchiveValue can handle this.
+			if (e == 2) // invalid key type (function, thread, lightuserdata, or anything we don't recognise)
+			{
+				lua_pushvalue(gL, -2);
+				CONS_Alert(CONS_ERROR, "Index '%s' (%s) of table %d could not be archived!\n", lua_tostring(gL, -1), luaL_typename(gL, -1), i);
+				lua_pop(gL, 1);
+			}
+			// Write value
 			e = ArchiveValue(TABLESINDEX, -1);
 			if (e == 1)
 				n++; // the table contained a new table we'll have to archive. :(
-			else if (e == 2)
+			else if (e == 2) // invalid value type
 			{
 				lua_pushvalue(gL, -2);
 				CONS_Alert(CONS_ERROR, "Type of value for table %d entry '%s' (%s) could not be archived!\n", i, lua_tostring(gL, -1), luaL_typename(gL, -1));
@@ -1016,11 +1024,17 @@ static void UnArchiveTables(void)
 		lua_rawgeti(gL, TABLESINDEX, i);
 		while (true)
 		{
-			if (UnArchiveValue(TABLESINDEX) == 1)
+			if (UnArchiveValue(TABLESINDEX) == 1) // read key
 				break;
-			if (UnArchiveValue(TABLESINDEX) == 2)
+			if (UnArchiveValue(TABLESINDEX) == 2) // read value
 				n++;
-			lua_rawset(gL, -3);
+			if (lua_isnil(gL, -2)) // if key is nil (if a function etc was accidentally saved)
+			{
+				CONS_Alert(CONS_ERROR, "A nil key in table %d was found! (Invalid key type or corrupted save?)\n", i);
+				lua_pop(gL, 2); // pop key and value instead of setting them in the table, to prevent Lua panic errors
+			}
+			else
+				lua_rawset(gL, -3);
 		}
 		lua_pop(gL, 1);
 	}