diff --git a/init.lua b/init.lua
index d317dc5..3130485 100644
--- a/init.lua
+++ b/init.lua
@@ -73,6 +73,7 @@ i3.files.callbacks()
 
 local storage = core.get_mod_storage()
 local slz, dslz, str_to_pos, add_hud_waypoint = i3.get("slz", "dslz", "str_to_pos", "add_hud_waypoint")
+local set_fs = i3.set_fs
 
 i3.data = dslz(storage:get_string "data") or {}
 
@@ -97,7 +98,7 @@ end
 
 if rawget(_G, "armor") then
 	i3.modules.armor = true
-	armor:register_on_update(i3.set_fs)
+	armor:register_on_update(set_fs)
 end
 
 if rawget(_G, "skins") then
@@ -108,20 +109,20 @@ if rawget(_G, "awards") then
 	i3.modules.awards = true
 
 	core.register_on_craft(function(_, player)
-		i3.set_fs(player)
+		set_fs(player)
 	end)
 
 	core.register_on_dignode(function(_, _, player)
-		i3.set_fs(player)
+		set_fs(player)
 	end)
 
 	core.register_on_placenode(function(_, _, player)
-		i3.set_fs(player)
+		set_fs(player)
 	end)
 
 	core.register_on_chat_message(function(name)
 		local player = core.get_player_by_name(name)
-		i3.set_fs(player)
+		set_fs(player)
 	end)
 end
 
@@ -164,7 +165,7 @@ local function init_data(player, info)
 	local inv = player:get_inventory()
 	inv:set_size("main", i3.INV_SIZE)
 
-	core.after(0, i3.set_fs, player)
+	core.after(0, set_fs, player)
 end
 
 local function init_waypoints(player)
diff --git a/src/bags.lua b/src/bags.lua
index e819e9e..a78fc08 100644
--- a/src/bags.lua
+++ b/src/bags.lua
@@ -1,3 +1,5 @@
+local set_fs = i3.set_fs
+local ItemStack = ItemStack
 local S, ES, fmt, msg, slz, dslz = i3.get("S", "ES", "fmt", "msg", "slz", "dslz")
 local play_sound, create_inventory = i3.get("play_sound", "create_inventory")
 
@@ -82,7 +84,7 @@ local function init_bags(player)
 				inv:set_list("main", get_content(content))
 			end
 
-			i3.set_fs(player)
+			set_fs(player)
 		end,
 
 		on_take = function()
@@ -92,7 +94,7 @@ local function init_bags(player)
 			local content = get_content_inv(name)
 			content:set_list("main", {})
 
-			i3.set_fs(player)
+			set_fs(player)
 		end,
 	}, name)
 
@@ -141,7 +143,7 @@ local function init_bags(player)
 		bag:set_stack("main", 1, bagstack)
 		data.bag_item = safe_format(bagstack)
 
-		i3.set_fs(player)
+		set_fs(player)
 	end
 
 	local bag_content = create_inventory(fmt("i3_bag_content_%s", name), {
diff --git a/src/callbacks.lua b/src/callbacks.lua
index 9256bc0..7710776 100644
--- a/src/callbacks.lua
+++ b/src/callbacks.lua
@@ -1,5 +1,7 @@
 local _, get_inventory_fs = i3.files.gui()
 
+local set_fs = i3.set_fs
+local ItemStack = ItemStack
 local S, clr = i3.get("S", "clr")
 local min, random = i3.get("min", "random")
 local reg_items, reg_aliases = i3.get("reg_items", "reg_aliases")
@@ -201,7 +203,7 @@ i3.new_tab("inventory", {
 			data.scrbar_inv = data.scrbar_inv + 1000
 		end
 
-		return i3.set_fs(player)
+		return set_fs(player)
 	end,
 })
 
@@ -308,7 +310,7 @@ local function rcp_fields(player, data, fields)
 	elseif fields.key_enter_field == "filter" or fields.search then
 		if fields.filter == "" then
 			reset_data(data)
-			return i3.set_fs(player)
+			return set_fs(player)
 		end
 
 		local str = lower(fields.filter)
@@ -430,7 +432,7 @@ core.register_on_player_receive_fields(function(player, formname, fields)
 		return true, tab.fields(player, data, fields)
 	end
 
-	return true, i3.set_fs(player)
+	return true, set_fs(player)
 end)
 
 core.register_on_player_hpchange(function(player, hpchange)
@@ -441,7 +443,7 @@ core.register_on_player_hpchange(function(player, hpchange)
 	local hp_max = player:get_properties().hp_max
 	data.hp = min(hp_max, player:get_hp() + hpchange)
 
-	i3.set_fs(player)
+	set_fs(player)
 end)
 
 core.register_on_dieplayer(function(player)
@@ -449,12 +451,12 @@ core.register_on_dieplayer(function(player)
 	local data = i3.data[name]
 	if not data then return end
 
-	i3.set_fs(player)
+	set_fs(player)
 end)
 
 core.register_on_chatcommand(function(name)
 	local player = core.get_player_by_name(name)
-	core.after(0, i3.set_fs, player)
+	core.after(0, set_fs, player)
 end)
 
 core.register_on_priv_grant(function(name, _, priv)
@@ -464,7 +466,7 @@ core.register_on_priv_grant(function(name, _, priv)
 		data.favs = {}
 
 		local player = core.get_player_by_name(name)
-		core.after(0, i3.set_fs, player)
+		core.after(0, set_fs, player)
 	end
 end)
 
@@ -475,6 +477,6 @@ core.register_on_player_inventory_action(function(player, _, _, info)
 	  ((info.from_list == "main"  and info.to_list == "craft") or
 	   (info.from_list == "craft" and info.to_list == "main")  or
 	   (info.from_list == "craftresult" and info.to_list == "main")) then
-		i3.set_fs(player)
+		set_fs(player)
 	end
 end)
diff --git a/src/common.lua b/src/common.lua
index 5ea32f0..d2697e3 100644
--- a/src/common.lua
+++ b/src/common.lua
@@ -1,3 +1,7 @@
+local ItemStack = ItemStack
+local loadstring = loadstring
+local sort, concat, insert = table.sort, table.concat, table.insert
+local min, floor, ceil = math.min, math.floor, math.ceil
 local fmt, find, match, gmatch, sub, split, lower =
 	string.format, string.find, string.match, string.gmatch, string.sub, string.split, string.lower
 
@@ -54,7 +58,7 @@ end
 
 local function round(num, decimal)
 	local mul = 10 ^ decimal
-	return math.floor(num * mul + 0.5) / mul
+	return floor(num * mul + 0.5) / mul
 end
 
 local function search(data)
@@ -243,7 +247,7 @@ local function groups_to_items(groups, get_all)
 	for name, def in pairs(core.registered_items) do
 		if show_item(def) and item_has_groups(def.groups, groups) then
 			if get_all then
-				names[#names + 1] = name
+				insert(names, name)
 			else
 				return name
 			end
@@ -304,7 +308,7 @@ local function sort_by_category(data)
 		end
 
 		if to_add then
-			new[#new + 1] = item
+			insert(new, item)
 		end
 	end
 
@@ -369,7 +373,7 @@ local function craft_stack(player, data, craft_rcp)
 			for _, item in ipairs(item_groups) do
 			for _name, _count in pairs(data.export_counts[rcp_usg].inv) do
 				if item == _name and remaining > 0 then
-					local c = math.min(remaining, _count)
+					local c = min(remaining, _count)
 					items[item] = c
 					remaining = remaining - c
 				end
@@ -385,11 +389,11 @@ local function craft_stack(player, data, craft_rcp)
 	end
 
 	local count = stackcount * scrbar_val
-	local iter = math.ceil(count / stackmax)
+	local iter = ceil(count / stackmax)
 	local leftover = count
 
 	for _ = 1, iter do
-		local c = math.min(stackmax, leftover)
+		local c = min(stackmax, leftover)
 		local stack = ItemStack(fmt("%s %s", stackname, c))
 		get_stack(player, stack)
 		leftover = leftover - stackmax
@@ -423,7 +427,7 @@ local function get_sorting_idx(name)
 end
 
 local function sorter(inv, reverse, mode)
-	table.sort(inv, function(a, b)
+	sort(inv, function(a, b)
 		if mode == 1 then
 			a, b = a:get_name(), b:get_name()
 		else
@@ -449,9 +453,9 @@ local function pre_sorting(list, start_i)
 
 		if not empty then
 			if next(meta.fields) or wear then
-				special[#special + 1] = stack
+				insert(special, stack)
 			else
-				new_inv[#new_inv + 1] = stack
+				insert(new_inv, stack)
 			end
 		end
 	end
@@ -474,7 +478,7 @@ local function compress_items(list, start_i)
 
 		if not empty then
 			if next(meta.fields) or wear or count >= stackmax then
-				special[#special + 1] = stack
+				insert(special, stack)
 			else
 				hash[name] = hash[name] or 0
 				hash[name] = hash[name] + count
@@ -484,11 +488,11 @@ local function compress_items(list, start_i)
 
 	for name, count in pairs(hash) do
 		local stackmax = ItemStack(name):get_stack_max()
-		local iter = math.ceil(count / stackmax)
+		local iter = ceil(count / stackmax)
 		local leftover = count
 
 		for _ = 1, iter do
-			new_inv[#new_inv + 1] = ItemStack(fmt("%s %u", name, math.min(stackmax, leftover)))
+			insert(new_inv, ItemStack(fmt("%s %u", name, min(stackmax, leftover))))
 			leftover = leftover - stackmax
 		end
 	end
@@ -555,6 +559,24 @@ local function add_hud_waypoint(player, name, pos, color)
 	}
 end
 
+local function createunpack(n)
+	local ret = {"local t = ... return "}
+
+	for k = 2, n do
+		ret[2 + (k - 2) * 4] = "t["
+		ret[3 + (k - 2) * 4] = k - 1
+		ret[4 + (k - 2) * 4] = "]"
+
+		if k ~= n then
+			ret[5 + (k - 2) * 4] = ","
+		end
+	end
+
+	return loadstring(concat(ret))
+end
+
+local newunpack = createunpack(33)
+
 -------------------------------------------------------------------------------
 
 local _ = {
@@ -640,6 +662,7 @@ local _ = {
 	insert = table.insert,
 	remove = table.remove,
 	indexof = table.indexof,
+	unpack = newunpack,
 	is_table = is_table,
 	table_merge = table_merge,
 	table_replace = table_replace,
@@ -668,5 +691,5 @@ function i3.get(...)
 		t[i] = _[var]
 	end
 
-	return unpack(t)
+	return newunpack(t)
 end
diff --git a/src/detached_inv.lua b/src/detached_inv.lua
index 9b4ceb2..24879bb 100644
--- a/src/detached_inv.lua
+++ b/src/detached_inv.lua
@@ -1,3 +1,4 @@
+local set_fs = i3.set_fs
 local fmt, play_sound, create_inventory = i3.get("fmt", "play_sound", "create_inventory")
 
 local trash = create_inventory("i3_trash", {
@@ -12,7 +13,7 @@ local trash = create_inventory("i3_trash", {
 		play_sound(name, "i3_trash", 1.0)
 
 		if not core.is_creative_enabled(name) then
-			i3.set_fs(player)
+			set_fs(player)
 		end
 	end,
 })
diff --git a/src/gui.lua b/src/gui.lua
index 57eea9f..27bab22 100644
--- a/src/gui.lua
+++ b/src/gui.lua
@@ -3,13 +3,14 @@ local damage_enabled = core.settings:get_bool "enable_damage"
 local model_aliases = i3.files.model_alias()
 local PNG, styles, fs_elements, colors = i3.files.styles()
 
+local ItemStack = ItemStack
 local S, ES, translate = i3.get("S", "ES", "translate")
 local clr, ESC, check_privs = i3.get("clr", "ESC", "check_privs")
 local min, max, floor, ceil, round = i3.get("min", "max", "floor", "ceil", "round")
 local sprintf, find, match, sub, upper = i3.get("fmt", "find", "match", "sub", "upper")
 local reg_items, reg_tools, reg_entities = i3.get("reg_items", "reg_tools", "reg_entities")
-local maxn, sort, concat, copy, insert, remove =
-	i3.get("maxn", "sort", "concat", "copy", "insert", "remove")
+local maxn, sort, concat, copy, insert, remove, unpack =
+	i3.get("maxn", "sort", "concat", "copy", "insert", "remove", "unpack")
 
 local true_str, is_fav, is_num = i3.get("true_str", "is_fav", "is_num")
 local groups_to_items, compression_active, compressible =
@@ -193,19 +194,19 @@ local function get_award_list(data, fs, ctn_len, yextra, award_list, awards_unlo
 			icon = fmt("%s^\\[colorize:#000:180", icon)
 		end
 
-		fs[#fs + 1] = fmt("image", 0, y + 0.01, icon_size, icon_size, icon)
-		fs[#fs + 1] = "style_type[box;colors=#bababa30,#bababa30,#bababa05,#bababa05]"
-		fs[#fs + 1] = fmt("box", icon_size + 0.1, y, box_len, icon_size, "")
+		insert(fs, fmt("image", 0, y + 0.01, icon_size, icon_size, icon))
+		insert(fs, "style_type[box;colors=#bababa30,#bababa30,#bababa05,#bababa05]")
+		insert(fs, fmt("box", icon_size + 0.1, y, box_len, icon_size, ""))
 
 		if progress then
 			local current, target = progress.current, progress.target
 			local curr_bar = (current * box_len) / target
 
-			fs[#fs + 1] = fmt("box", icon_size + 0.1, y + 0.8, box_len, 0.3, "#101010")
-			fs[#fs + 1] = "style_type[box;colors=#9dc34c80,#9dc34c,#9dc34c,#9dc34c80]"
-			fs[#fs + 1] = fmt("box", icon_size + 0.1, y + 0.8, curr_bar, 0.3, "")
-			fs[#fs + 1] = "style_type[label;font_size=14]"
-			fs[#fs + 1] = fmt("label", icon_size + 0.5, y + 0.97, fmt("%u / %u", current, target))
+			insert(fs, fmt("box", icon_size + 0.1, y + 0.8, box_len, 0.3, "#101010"))
+			insert(fs, "style_type[box;colors=#9dc34c80,#9dc34c,#9dc34c,#9dc34c80]")
+			insert(fs, fmt("box", icon_size + 0.1, y + 0.8, curr_bar, 0.3, ""))
+			insert(fs, "style_type[label;font_size=14]")
+			insert(fs, fmt("label", icon_size + 0.5, y + 0.97, fmt("%u / %u", current, target)))
 
 			y = y - 0.14
 		end
@@ -213,11 +214,11 @@ local function get_award_list(data, fs, ctn_len, yextra, award_list, awards_unlo
 		title = _title or title
 		desc = _desc or desc
 
-		fs[#fs + 1] = "style_type[label;font=bold;font_size=17]"
-		fs[#fs + 1] = fmt("label", icon_size + 0.2, y + 0.4, title)
-		fs[#fs + 1] = "style_type[label;font=normal;font_size=15]"
-		fs[#fs + 1] = fmt("label", icon_size + 0.2, y + 0.75, clr("#bbbbbb", desc))
-		fs[#fs + 1] = "style_type[label;font_size=16]"
+		insert(fs, "style_type[label;font=bold;font_size=17]")
+		insert(fs, fmt("label", icon_size + 0.2, y + 0.4, title))
+		insert(fs, "style_type[label;font=normal;font_size=15]")
+		insert(fs, fmt("label", icon_size + 0.2, y + 0.75, clr("#bbbbbb", desc)))
+		insert(fs, "style_type[label;font_size=16]")
 	end
 end
 
@@ -385,7 +386,7 @@ local function get_container(fs, data, player, yoffset, ctn_len, award_list, awa
 					id = i
 				end
 
-				sks[#sks + 1] = skin.name
+				insert(sks, skin.name)
 			end
 
 			sks = concat(sks, ","):gsub(";", "")
@@ -527,7 +528,7 @@ local function get_inventory_fs(player, data, fs)
 		local t = {}
 
 		for _, v in ipairs(props.textures) do
-			t[#t + 1] = ESC(v):gsub(",", "!")
+			insert(t, (ESC(v):gsub(",", "!")))
 		end
 
 		local textures = concat(t, ","):gsub("!", ",")
@@ -864,7 +865,7 @@ local function get_grid_fs(fs, data, rcp, is_recipe)
 
 				if not added then
 					label = fmt("%s%s\nR", label ~= "" and "\n" or "", label)
-					replace.items[#replace.items + 1] = replacement[2]
+					insert(replace.items, replacement[2])
 				end
 			end
 		end
@@ -980,11 +981,11 @@ local function get_model_fs(fs, data, def, model_alias)
 			_name = fmt("%s^[verticalframe:%u:0", v.name, v.animation.frames_h or v.animation.aspect_h)
 		end
 
-		t[#t + 1] = _name or v.name or v
+		insert(t, _name or v.name or v)
 	end
 
 	while #t < 6 do
-		t[#t + 1] = t[#t]
+		insert(t, t[#t])
 	end
 
 	fs("model", data.inv_width + 6.6, data.yoffset + 0.05, 1.3, 1.3, "preview",
@@ -1124,7 +1125,7 @@ local function get_items_fs(fs, data, full_height)
 		for i = 1, #data.items do
 			local item = data.items[i]
 			if not i3.compressed[item] then
-				new[#new + 1] = item
+				insert(new, item)
 			end
 		end
 
@@ -1175,7 +1176,7 @@ local function get_items_fs(fs, data, full_height)
 			local Y = round((i % ipp - X) / rows + 1, 0)
 			      Y = Y - (Y * 0.085) + 0.95
 
-			fs[#fs + 1] = fmt("item_image_button", X, Y, size, size, name, item, "")
+			insert(fs, fmt("item_image_button", X, Y, size, size, name, item, ""))
 
 			if compressible(item, data) then
 				local expand = data.expand == name
@@ -1340,9 +1341,9 @@ local function make_fs(player, data)
 			local elem = fs_elements[args[1]]
 
 			if elem then
-				t[#t + 1] = fmt(elem, select(2, ...))
+				insert(t, fmt(elem, select(2, ...)))
 			else
-				t[#t + 1] = concat(args)
+				insert(t, concat(args))
 			end
 		end
 	})
diff --git a/src/progressive.lua b/src/progressive.lua
index 4be1311..385cbcc 100644
--- a/src/progressive.lua
+++ b/src/progressive.lua
@@ -1,5 +1,6 @@
 local singleplayer = core.is_singleplayer()
 
+local set_fs = i3.set_fs
 local fmt, search, table_merge, array_diff =
 	i3.get("fmt", "search", "table_merge", "array_diff")
 local is_group, extract_groups, item_has_groups, apply_recipe_filters =
@@ -225,7 +226,7 @@ local function poll_new_items()
 			data.itab = 1
 
 			search(data)
-			i3.set_fs(player)
+			set_fs(player)
 		end
 	end
 
diff --git a/src/recipes.lua b/src/recipes.lua
index caaffd6..e3408ea 100644
--- a/src/recipes.lua
+++ b/src/recipes.lua
@@ -1,5 +1,6 @@
 local replacements = {fuel = {}}
 
+local ItemStack = ItemStack
 local fmt, reg_items, reg_aliases = i3.get("fmt", "reg_items", "reg_aliases")
 local maxn, copy, insert, sort, match = i3.get("maxn", "copy", "insert", "sort", "match")
 
@@ -244,7 +245,7 @@ local function resolve_aliases(hash)
 		end
 
 		if newname ~= "" and i3.recipes_cache[oldname] and not hash[newname] then
-			i3.init_items[#i3.init_items + 1] = newname
+			insert(i3.init_items, newname)
 		end
 	end
 end
@@ -265,7 +266,7 @@ local function init_recipes()
 	for name in pairs(_preselect) do
 		cache_usages(name)
 
-		i3.init_items[#i3.init_items + 1] = name
+		insert(i3.init_items, name)
 		_select[name] = true
 	end