diff --git a/code/__defines/subsystem-priority.dm b/code/__defines/subsystem-priority.dm
index 8b5ea99a121..fb9a484227f 100644
--- a/code/__defines/subsystem-priority.dm
+++ b/code/__defines/subsystem-priority.dm
@@ -25,9 +25,9 @@
 #define SS_INIT_SUNLIGHT    1	// Sunlight setup. Creates lots of lighting & SSzcopy updates.
 #define SS_INIT_LIGHTING    0	// Generation of lighting overlays and pre-bake. May cause openturf updates, should initialize before SSzcopy.
 #define SS_INIT_ZCOPY      -1	// Z-mimic flush. Should run after SSoverlay & SSicon_smooth so it copies the smoothed sprites.
-#define SS_INIT_LOBBY      -2	// Lobby timer starts here. The lobby timer won't actually start going down until the MC starts ticking, so you probably want this last
-#define SS_INIT_CHAT       -3	// To ensure chat remains smooth during init.
-#define SS_INIT_XENOARCH   -4   // Xenoarch is this far below because it can infinite loop if placed in SS_INIT_MISC as it was before, due to some subsystems spawning stuff there.
+#define SS_INIT_XENOARCH   -2   // Xenoarch is this far below because it can infinite loop if placed in SS_INIT_MISC as it was before, due to some subsystems spawning stuff there.
+#define SS_INIT_LOBBY      -3	// Lobby timer starts here. The lobby timer won't actually start going down until the MC starts ticking, so you probably want this last
+#define SS_INIT_CHAT       -4	// To ensure chat remains smooth during init.
 
 // Something to remember when setting priorities: SS_TICKER runs before Normal, which runs before SS_BACKGROUND.
 // Each group has its own priority bracket.
diff --git a/code/controllers/subsystems/lighting.dm b/code/controllers/subsystems/lighting.dm
index 95f2deec4b5..d894353533c 100644
--- a/code/controllers/subsystems/lighting.dm
+++ b/code/controllers/subsystems/lighting.dm
@@ -76,6 +76,11 @@ var/datum/controller/subsystem/lighting/SSlighting
 	for (var/zlevel = 1 to world.maxz)
 		for (thing in Z_ALL_TURFS(zlevel))
 			T = thing
+			if(config.starlight)
+				var/turf/space/S = T
+				if(istype(S) && S.use_starlight)
+					S.update_starlight()
+
 			if (!T.dynamic_lighting)
 				continue
 
diff --git a/code/datums/ruins.dm b/code/datums/ruins.dm
index c9d521c9423..d279468f55d 100644
--- a/code/datums/ruins.dm
+++ b/code/datums/ruins.dm
@@ -12,7 +12,7 @@
 
 	var/prefix = null
 	var/suffix = null
-	template_flags = 0 // No duplicates by default
+	template_flags = TEMPLATE_FLAG_NO_RUINS // Don't let ruins spawn on top of ruins
 
 	// !! Currently only implemented for away sites
 	var/list/force_ruins // Listed ruins are always spawned unless disallowed by flags.
diff --git a/code/game/turfs/space/space.dm b/code/game/turfs/space/space.dm
index f48e7791ddb..576d40ff7e6 100644
--- a/code/game/turfs/space/space.dm
+++ b/code/game/turfs/space/space.dm
@@ -25,7 +25,7 @@
 /turf/space/Initialize()
 	if(use_space_appearance)
 		appearance = SSskybox.space_appearance_cache[(((x + y) ^ ~(x * y) + z) % 25) + 1]
-	if(config.starlight && use_starlight)
+	if(config.starlight && use_starlight && lighting_overlays_initialized)
 		update_starlight()
 
 	if (initialized)
@@ -62,12 +62,10 @@
 
 	return 0
 
-/turf/space/proc/update_starlight(var/validate = TRUE)
+/turf/space/proc/update_starlight()
 	if(!config.starlight)
 		return
-	if(!validate) // basically a hack for places where the check was already done for us
-		set_light(1, config.starlight, l_color = SSskybox.background_color)
-	else if(locate(/turf/simulated) in RANGE_TURFS(1, src))
+	if(locate(/turf/simulated) in RANGE_TURFS(1, src))
 		set_light(1, config.starlight, l_color = SSskybox.background_color)
 	else
 		set_light(0)
diff --git a/code/game/turfs/turf_changing.dm b/code/game/turfs/turf_changing.dm
index 49cb5eee16d..668eab2793c 100644
--- a/code/game/turfs/turf_changing.dm
+++ b/code/game/turfs/turf_changing.dm
@@ -83,9 +83,9 @@
 			else
 				lighting_clear_overlay()
 
-	if (config.starlight)
-		for (var/turf/space/S in RANGE_TURFS(1, src))
-			S.update_starlight(FALSE)
+		if (config.starlight)
+			for (var/turf/space/S in RANGE_TURFS(1, src))
+				S.update_starlight()
 
 	W.above = old_above
 
diff --git a/code/modules/random_map/random_map.dm b/code/modules/random_map/random_map.dm
index bb769caed00..b4a7effd854 100644
--- a/code/modules/random_map/random_map.dm
+++ b/code/modules/random_map/random_map.dm
@@ -50,7 +50,7 @@ var/global/list/map_count = list()
 	if(tlx) limit_x = tlx
 	if(tly) limit_y = tly
 
-	if(used_area)
+	if(!use_area && used_area)
 		if(ispath(used_area))
 			use_area = new(used_area)
 		else
@@ -186,7 +186,7 @@ var/global/list/map_count = list()
 	if(!T || (target_turf_type && !istype(T,target_turf_type)))
 		return 0
 	var/newpath = get_appropriate_path(map[tmp_cell])
-	if(newpath)
+	if(newpath && !istype(T, newpath))
 		T.ChangeTurf(newpath)
 	if(spawn_roof)
 		T.spawn_roof()
diff --git a/html/changelogs/johnwildkins-fixlag2.yml b/html/changelogs/johnwildkins-fixlag2.yml
new file mode 100644
index 00000000000..606fb5f1d8b
--- /dev/null
+++ b/html/changelogs/johnwildkins-fixlag2.yml
@@ -0,0 +1,9 @@
+author: JohnWildkins
+
+delete-after: True
+
+changes:
+  - bugfix: "Ruins should no longer generate on top of each other."
+  - backend: "Starlight generation is now handled in SSlighting, so temporary space tiles are not calculated."
+  - backend: "Fixed an issue where exoplanets were creating 2x as many necessary space tiles during generation."
+  - backend: "Moved SSxenoarch init above SSlobby."
diff --git a/maps/sccv_horizon/code/sccv_horizon.dm b/maps/sccv_horizon/code/sccv_horizon.dm
index be1d2d6ccce..0bd3ebc332d 100644
--- a/maps/sccv_horizon/code/sccv_horizon.dm
+++ b/maps/sccv_horizon/code/sccv_horizon.dm
@@ -126,7 +126,3 @@
 	allow_borgs_to_leave = TRUE
 
 	warehouse_basearea = /area/operations/storage
-
-/datum/map/sccv_horizon/finalize_load()
-	// generate an empty space Z
-	world.maxz++