diff --git a/.luacheckrc b/.luacheckrc
new file mode 100644
index 0000000..995f9ab
--- /dev/null
+++ b/.luacheckrc
@@ -0,0 +1,21 @@
+unused_args = false
+allow_defined_top = true
+
+globals = {
+	"missions",
+	"minetest"
+}
+
+read_globals = {
+	-- Stdlib
+	string = {fields = {"split"}},
+	table = {fields = {"copy", "getn"}},
+	"call",
+
+	-- Minetest
+	"vector", "ItemStack",
+	"dump", "VoxelArea",
+
+	-- Deps
+	"unified_inventory", "default", "xp_redo"
+}
diff --git a/block.lua b/block.lua
index f2fb12d..85a18e1 100644
--- a/block.lua
+++ b/block.lua
@@ -34,8 +34,6 @@ minetest.register_node("missions:mission", {
 			-- target inv empty
 
 			local steps = missions.get_steps(pos)
-			local meta = minetest.get_meta(pos)
-
 			local selected_step = missions.get_selected_list_item(player)
 
 			local step = steps[selected_step]
diff --git a/executor.hud.lua b/executor.hud.lua
index 75ec22e..5d71671 100644
--- a/executor.hud.lua
+++ b/executor.hud.lua
@@ -64,7 +64,7 @@ missions.hud_update_status = function(player, status)
 	player:hud_change(data.status, "text", status)
 end
 
-missions.hud_update = function(player, mission, remainingTime)
+missions.hud_update = function(player, mission)
 
 	local playername = player:get_player_name()
 	local data = hud[playername]
diff --git a/executor.lua b/executor.lua
index c0de7f9..3673b7d 100644
--- a/executor.lua
+++ b/executor.lua
@@ -62,7 +62,7 @@ local update_mission = function(mission, player)
 
 	local success = false
 	local failed = false
-	
+
 	local on_success = function()
 		success = true
 	end
@@ -173,7 +173,6 @@ minetest.register_globalstep(function(dtime)
 	if timer >= 0.5 then
 		local players = minetest.get_connected_players()
 		for i,player in ipairs(players) do
-			local playername = player:get_player_name()
 			local mission = missions.get_current_mission(player)
 
 			if mission then
@@ -185,4 +184,4 @@ minetest.register_globalstep(function(dtime)
 
 		timer = 0
 	end
-end)
\ No newline at end of file
+end)
diff --git a/form.missionblock_config.lua b/form.missionblock_config.lua
index 2987e3c..afeefd7 100644
--- a/form.missionblock_config.lua
+++ b/form.missionblock_config.lua
@@ -7,7 +7,6 @@ missions.form.missionblock_config = function(pos, node, player)
 
 	local name = meta:get_string("name")
 	local time = meta:get_string("time")
-	local owner = meta:get_string("owner")
 	local description = meta:get_string("description")
 	local hidden = meta:get_int("hidden")
 
diff --git a/form.missionblock_main.lua b/form.missionblock_main.lua
index fc25946..b9b4940 100644
--- a/form.missionblock_main.lua
+++ b/form.missionblock_main.lua
@@ -47,7 +47,6 @@ minetest.register_on_player_receive_fields(function(player, formname, fields)
 	end
 
 	local pos = minetest.string_to_pos(parts[2])
-	local meta = minetest.get_meta(pos)
 	local node = minetest.get_node(pos)
 
 	if not missions.check_owner(pos, player) then
diff --git a/form.missionblock_stepeditor.lua b/form.missionblock_stepeditor.lua
index 32712b2..cc69ad4 100644
--- a/form.missionblock_stepeditor.lua
+++ b/form.missionblock_stepeditor.lua
@@ -3,8 +3,6 @@ local FORMNAME = "mission_block_stepeditor"
 
 missions.form.missionblock_stepeditor = function(pos, node, player)
 
-	local meta = minetest.get_meta(pos)
-
 	local selected_step = missions.get_selected_list_item(player)
 	local steps = missions.get_steps(pos)
 
@@ -27,7 +25,7 @@ missions.form.missionblock_stepeditor = function(pos, node, player)
 		"button[5.5,3;2,1;up;Up]" ..
 		"button[5.5,4;2,1;down;Down]" ..
 		"button[5.5,5;2,1;remove;Remove]" ..
-		steps_list .. 
+		steps_list ..
 		"button_exit[0,7;8,1;save;Save and validate]" ..
 		missions.FORMBG
 
diff --git a/form.missionblock_user.lua b/form.missionblock_user.lua
index 2a01e75..624028d 100644
--- a/form.missionblock_user.lua
+++ b/form.missionblock_user.lua
@@ -32,8 +32,6 @@ minetest.register_on_player_receive_fields(function(player, formname, fields)
 	end
 
 	local pos = minetest.string_to_pos(parts[2])
-	local meta = minetest.get_meta(pos)
-	local node = minetest.get_node(pos)
 
 	if fields.start then
 		local result = missions.validate_mission(pos, player)
@@ -46,4 +44,4 @@ minetest.register_on_player_receive_fields(function(player, formname, fields)
 	end
 
 
-end)
\ No newline at end of file
+end)
diff --git a/form.newstep.lua b/form.newstep.lua
index 01e8d77..7f1be7d 100644
--- a/form.newstep.lua
+++ b/form.newstep.lua
@@ -22,9 +22,6 @@ end
 
 missions.form.newstep = function(pos, node, player)
 
-	local step_buttons = ""
-	local offset = 1
-
 	local steps = get_mission_steps_for_player(player)
 	local list = ""
 	for i,spec in ipairs(steps) do
@@ -96,7 +93,7 @@ minetest.register_on_player_receive_fields(function(player, formname, fields)
 			data = stepdata
 		}
 
-		local steps = missions.get_steps(pos)
+		steps = missions.get_steps(pos)
 		table.insert(steps, step)
 
 		missions.set_steps(pos, steps)
diff --git a/form.wand.lua b/form.wand.lua
index b9b1a03..d95b192 100644
--- a/form.wand.lua
+++ b/form.wand.lua
@@ -41,8 +41,8 @@ minetest.register_on_player_receive_fields(function(player, formname, fields)
 	local meta = stack:get_meta()
 	meta:set_string("pos", posStr)
 	meta:set_string("name", fields.name)
-	meta:set_string("description", "Mission wand (" .. type .. "): " .. posStr .. 
-		" with name: '" .. fields.name .. 
+	meta:set_string("description", "Mission wand (" .. type .. "): " .. posStr ..
+		" with name: '" .. fields.name ..
 		"' and node '" .. node.name .. "'")
 
 	if inv:contains_item("main", "missions:wand") and inv:room_for_item("main", stack) then
diff --git a/functions.lua b/functions.lua
index fd179b4..4b9b643 100644
--- a/functions.lua
+++ b/functions.lua
@@ -1,4 +1,3 @@
-local has_xp_redo_mod = minetest.get_modpath("xp_redo")
 
 missions.check_owner = function(pos, player)
 	-- check override priv
@@ -40,7 +39,6 @@ minetest.register_on_joinplayer(function(player)
 	if mission and mission.version == missions.CURRENT_MISSION_SPEC_VERSION then
 		-- only load if compatible with current spec
 		local step = mission.steps[mission.currentstep]
-		
 		if step == nil then
 			return
 		end
@@ -158,7 +156,7 @@ end
 missions.get_image = function(name)
 	-- stolen from drawers code
 	local texture = "blank.png"
-	local def = core.registered_items[name]
+	local def = minetest.registered_items[name]
 	if not def then
 		return texture
 	end
@@ -178,11 +176,11 @@ missions.get_image = function(name)
 		-- tiles: up, down, right, left, back, front
 		-- inventorycube: up, front, right
 		if #tiles <= 2 then
-		        texture = core.inventorycube(tiles[1], tiles[1], tiles[1])
+		        texture = minetest.inventorycube(tiles[1], tiles[1], tiles[1])
 		elseif #tiles <= 5 then
-		        texture = core.inventorycube(tiles[1], tiles[3], tiles[3])
+		        texture = minetest.inventorycube(tiles[1], tiles[3], tiles[3])
 		else -- full tileset
-		        texture = core.inventorycube(tiles[1], tiles[6], tiles[3])
+		        texture = minetest.inventorycube(tiles[1], tiles[6], tiles[3])
 		end
 	end
 
diff --git a/hud.lua b/hud.lua
index 4458799..86932d8 100644
--- a/hud.lua
+++ b/hud.lua
@@ -5,36 +5,6 @@ local HUD_ALIGNMENT = {x = 1, y = 0}
 local hud = {} -- playerName -> {}
 
 
--- returns the image (item, node, tool) or ""
-local get_image = function(name)
-	-- minetest.registered_items[name].inventory_image
-	-- minetest.registered_tools[name].inventory_image
-	-- minetest.registered_nodes["default:stone"].tiles[1]
-	-- TODO: look at drawer code
-
-	if name == nil then
-		return ""
-	end
-
-	local node = minetest.registered_nodes[name]
-	if node ~= nil and node.tiles ~= nil and table.getn(node.tiles) == 1 then
-		return minetest.inventorycube(node.tiles[1],node.tiles[1],node.tiles[1])
-	end
-
-	local item = minetest.registered_items[name]
-	if item ~= nil and item.inventory_image ~= nil then
-		return item.inventory_image
-	end
-
-	local tool = minetest.registered_tools[name]
-	if tool ~= nil and tool.inventory_image ~= nil then
-		return tool.inventory_image
-	end
-
-	-- none found
-	return ""
-end
-
 minetest.register_on_joinplayer(function(player)
 	local playername = player:get_player_name()
 
@@ -161,16 +131,7 @@ missions.hud_update = function(player, playermissions)
 		player:hud_change(data.title, "text", "")
 		player:hud_change(data.mission, "text", "")
 		player:hud_change(data.time, "text", "")
-
-		local i = 1
-		while i <= hud_context_count do -- 1..n
-			player:hud_change(data.context[i], "text", "")
-			player:hud_change(data.contextcount[i], "text", "")
-
-			i = i + 1
-		end
 	end
-	
 end
 
 
diff --git a/register_step.lua b/register_step.lua
index 19e7a7c..d179b4f 100644
--- a/register_step.lua
+++ b/register_step.lua
@@ -9,7 +9,7 @@ missions.get_step_spec_by_type = function(type)
 	for i,spec in ipairs(missions.steps) do
 		if type == spec.type then
 			-- step spec found
-			return spec			
+			return spec
 		end
 	end
 end
@@ -91,7 +91,6 @@ minetest.register_on_player_receive_fields(function(player, formname, fields)
 			missions.set_steps(pos, steps)
 		end
 	end
-	
 
 end)
 
diff --git a/steps/build.lua b/steps/build.lua
index 2e2c9e6..7731bda 100644
--- a/steps/build.lua
+++ b/steps/build.lua
@@ -26,7 +26,6 @@ missions.register_step({
 
 		local formspec = "size[8,8;]" ..
 			"label[0,0;Place any nodes]" ..
-	
 			"field[0,2;8,1;count;Count;" .. stepdata.count ..  "]" ..
 			"button[0,7;8,1;save;Save]"
 
diff --git a/steps/buildspecific.lua b/steps/buildspecific.lua
index ef1a108..e74f58f 100644
--- a/steps/buildspecific.lua
+++ b/steps/buildspecific.lua
@@ -26,7 +26,6 @@ missions.register_step({
 
 	get_status = function(ctx)
 		local player = ctx.player
-		local stepdata = ctx.step.data
 		local name = player:get_player_name()
 
 		local stack = ItemStack(stacks[name] or "")
@@ -116,9 +115,9 @@ missions.register_step({
 	end,
 
 	on_step_exit = function(ctx)
-		local player = ctx.player;		
+		local player = ctx.player
 		local name = player:get_player_name()
-		local hud_data = hud[name];
+		local hud_data = hud[name]
 
 		if hud_data and hud_data.image then
 			player:hud_remove(hud_data.image)
diff --git a/steps/checkxp.lua b/steps/checkxp.lua
index d0c6f80..011d860 100644
--- a/steps/checkxp.lua
+++ b/steps/checkxp.lua
@@ -14,7 +14,6 @@ missions.register_step({
 
 		local formspec = "size[8,8;]" ..
 			"label[0,0;XP Check (Step #" .. stepnumber .. ")]" ..
-	
 			"field[0,2;8,1;xp;XP Threshold;" .. stepdata.xp ..  "]" ..
 			"button[0,7;8,1;save;Save]"
 
diff --git a/steps/chestput.lua b/steps/chestput.lua
index ab4c10b..e9aa913 100644
--- a/steps/chestput.lua
+++ b/steps/chestput.lua
@@ -82,7 +82,7 @@ missions.register_step({
 
 		if stepdata.pos then
 			local distance = vector.distance(ctx.pos, stepdata.pos)
-			name = name .. "Position(" .. stepdata.pos.x .. "/" .. 
+			name = name .. "Position(" .. stepdata.pos.x .. "/" ..
 				stepdata.pos.y .. "/" .. stepdata.pos.z ..") " ..
 				"Distance: " .. math.floor(distance) .. " m"
 		end
@@ -204,13 +204,13 @@ missions.register_step({
 
 		local str = remainingItems[player:get_player_name()]
 		if str then
-			local stack = ItemStack(str);
+			local stack = ItemStack(str)
 
 			if stack:get_count() == 0 then
 				ctx.on_success()
 			end
 
-			local hud_data = hud[player:get_player_name()];
+			local hud_data = hud[player:get_player_name()]
 			player:hud_change(hud_data.counter, "text", stack:get_count() .. "x")
 		else
 			ctx.on_success()
@@ -218,10 +218,10 @@ missions.register_step({
 	end,
 
 	on_step_exit = function(ctx)
-		local player = ctx.player;		
+		local player = ctx.player
 
 		remainingItems[player:get_player_name()] = ""
-		local hud_data = hud[player:get_player_name()];
+		local hud_data = hud[player:get_player_name()]
 
 		if hud_data and hud_data.image then
 			player:hud_remove(hud_data.image)
@@ -251,7 +251,7 @@ local intercept_chest = function(name)
 		def.on_metadata_inventory_put = function(pos, listname, index, stack, player)
 			if player and player:is_player() then
 				local remStack = ItemStack(remainingItems[player:get_player_name()])
-				
+
 				if remStack:get_name() == stack:get_name() then
 					local count = remStack:get_count() - stack:get_count()
 					if count < 0 then count = 0 end
diff --git a/steps/chestreward.lua b/steps/chestreward.lua
index b900833..a792492 100644
--- a/steps/chestreward.lua
+++ b/steps/chestreward.lua
@@ -1,7 +1,5 @@
 
 
-local hud = {} -- playerName -> {}
-
 missions.register_step({
 
 	type = "chestreward",
@@ -83,7 +81,7 @@ missions.register_step({
 
 		if stepdata.pos then
 			local distance = vector.distance(pos, stepdata.pos)
-			name = name .. "Position(" .. stepdata.pos.x .. "/" .. 
+			name = name .. "Position(" .. stepdata.pos.x .. "/" ..
 				stepdata.pos.y .. "/" .. stepdata.pos.z ..") " ..
 				"Distance: " .. math.floor(distance) .. " m"
 		end
diff --git a/steps/dig.lua b/steps/dig.lua
index 87b9ad8..ea7ef74 100644
--- a/steps/dig.lua
+++ b/steps/dig.lua
@@ -25,7 +25,6 @@ missions.register_step({
 
 		local formspec = "size[8,8;]" ..
 			"label[0,0;Dig any nodes]" ..
-	
 			"field[0,2;8,1;count;Count;" .. stepdata.count ..  "]" ..
 			"button[0,7;8,1;save;Save]"
 
diff --git a/steps/digspecific.lua b/steps/digspecific.lua
index 1f04fa0..a56a9c2 100644
--- a/steps/digspecific.lua
+++ b/steps/digspecific.lua
@@ -27,7 +27,6 @@ missions.register_step({
 
 	get_status = function(ctx)
 		local player = ctx.player
-		local stepdata = ctx.step.data
 		local name = player:get_player_name()
 
 		local stack = ItemStack(stacks[name] or "")
@@ -117,9 +116,9 @@ missions.register_step({
 	end,
 
 	on_step_exit = function(ctx)
-		local player = ctx.player;		
+		local player = ctx.player
 		local name = player:get_player_name()
-		local hud_data = hud[name];
+		local hud_data = hud[name]
 
 		if hud_data and hud_data.image then
 			player:hud_remove(hud_data.image)
diff --git a/steps/followup.lua b/steps/followup.lua
index 032ced6..a8eecfd 100644
--- a/steps/followup.lua
+++ b/steps/followup.lua
@@ -48,26 +48,22 @@ missions.register_step({
 
 	edit_formspec = function(ctx)
 		local pos = ctx.pos
-		local inv = ctx.inv
 		local stepdata = ctx.step.data
 
 		local name = ""
 
 		if stepdata.pos then
 			local distance = vector.distance(pos, stepdata.pos)
-			name = name .. "Position(" .. stepdata.pos.x .. "/" .. 
+			name = name .. "Position(" .. stepdata.pos.x .. "/" ..
 				stepdata.pos.y .. "/" .. stepdata.pos.z ..") " ..
 				"Distance: " .. math.floor(distance) .. " m"
 		end
 
 		local formspec = "size[8,8;]" ..
 			"label[0,0;Follow-up mission]" ..
-
 			"label[3,1;Target]" ..
 			"list[nodemeta:" .. pos.x .. "," .. pos.y .. "," .. pos.z .. ";main;4,1;1,1;0]" ..
-
 			"label[0,2;" .. name .. "]" ..
-
 			"list[current_player;main;0,6;8,1;]" ..
 			"button[0,7;8,1;save;Save]"
 
@@ -94,8 +90,8 @@ missions.register_step({
 	end,
 
 	on_step_enter = function(ctx)
-		local stepdata = ctx.step.data
-		local player = ctx.player
+		--local stepdata = ctx.step.data
+		--local player = ctx.player
 
 		--TODO
 		ctx.on_success()
diff --git a/steps/givebook.lua b/steps/givebook.lua
index eeef8a5..befebec 100644
--- a/steps/givebook.lua
+++ b/steps/givebook.lua
@@ -1,6 +1,5 @@
 
 
-local FORMNAME = "mission_block_step_message"
 
 missions.register_step({
 
@@ -18,7 +17,6 @@ missions.register_step({
 
 		local formspec = "size[8,8;]" ..
 			"label[0,0;Give a book]" ..
-	
 			"field[0,1;8,1;title;Title;" .. stepdata.title ..  "]" ..
 			"textarea[0,2;8,4;message;Message;" .. stepdata.message ..  "]" ..
 			"button[0,7;8,1;save;Save]"
@@ -46,7 +44,6 @@ missions.register_step({
 		local stepdata = ctx.step.data
 
 		local new_stack = ItemStack("default:book_written")
-		local stackMeta = new_stack:get_meta()
 
 		local data = {}
 
diff --git a/steps/givexp.lua b/steps/givexp.lua
index 08a821c..de66bdf 100644
--- a/steps/givexp.lua
+++ b/steps/givexp.lua
@@ -16,7 +16,6 @@ missions.register_step({
 
 		local formspec = "size[8,8;]" ..
 			"label[0,0;Give XP (Step #" .. stepnumber .. ")]" ..
-	
 			"field[0,2;8,1;xp;XP;" .. stepdata.xp ..  "]" ..
 			"button[0,7;8,1;save;Save]"
 
diff --git a/steps/grant.lua b/steps/grant.lua
index 73c0a88..79450c4 100644
--- a/steps/grant.lua
+++ b/steps/grant.lua
@@ -15,7 +15,6 @@ missions.register_step({
 
 		local formspec = "size[8,8;]" ..
 			"label[0,0;Grant privilege]" ..
-	
 			"field[0,2;8,1;priv;Privilege;" .. stepdata.priv ..  "]" ..
 			"button[0,7;8,1;save;Save]"
 
@@ -40,7 +39,7 @@ missions.register_step({
 		local name = player:get_player_name()
 		local stepdata = ctx.step.data
 		local priv = stepdata.priv
-	
+
 		if priv then
 			local privs = minetest.get_player_privs(name)
 			privs[priv] = true
diff --git a/steps/message.lua b/steps/message.lua
index 0428ed1..03ab9ea 100644
--- a/steps/message.lua
+++ b/steps/message.lua
@@ -17,7 +17,6 @@ missions.register_step({
 
 		local formspec = "size[8,8;]" ..
 			"label[0,0;Show a message]" ..
-	
 			"field[0,1;8,1;title;Title;" .. stepdata.title ..  "]" ..
 			"textarea[0,2;8,4;message;Message;" .. stepdata.message ..  "]" ..
 			"button[0,7;8,1;save;Save]"
diff --git a/steps/spawnmob.lua b/steps/spawnmob.lua
index af11efb..1d72fa0 100644
--- a/steps/spawnmob.lua
+++ b/steps/spawnmob.lua
@@ -62,7 +62,7 @@ missions.register_step({
 
 		if stepdata.pos then
 			local distance = vector.distance(pos, stepdata.pos)
-			name = name .. "Position(" .. stepdata.pos.x .. "/" .. 
+			name = name .. "Position(" .. stepdata.pos.x .. "/" ..
 				stepdata.pos.y .. "/" .. stepdata.pos.z ..") " ..
 				"Distance: " .. math.floor(distance) .. " m"
 		end
@@ -70,12 +70,12 @@ missions.register_step({
 
 		local selected = 1
 		local list = ""
-		for i,name in ipairs(mob_names) do
-			if name == stepdata.mobname then
+		for i,mname in ipairs(mob_names) do
+			if mname == stepdata.mobname then
 				selected = i
 			end
 
-			list = list .. minetest.formspec_escape(name)
+			list = list .. minetest.formspec_escape(mname)
 			if i < #mob_names then
 				-- not end of list
 				list = list .. ","
diff --git a/steps/teleport.lua b/steps/teleport.lua
index a85166c..cd66b73 100644
--- a/steps/teleport.lua
+++ b/steps/teleport.lua
@@ -41,7 +41,7 @@ missions.register_step({
 
 		if stepdata.pos then
 			local distance = vector.distance(pos, stepdata.pos)
-			name = name .. "Position(" .. stepdata.pos.x .. "/" .. 
+			name = name .. "Position(" .. stepdata.pos.x .. "/" ..
 				stepdata.pos.y .. "/" .. stepdata.pos.z ..") " ..
 				"Distance: " .. math.floor(distance) .. " m"
 		end
diff --git a/steps/waypoint.lua b/steps/waypoint.lua
index 60b6235..7c3566d 100644
--- a/steps/waypoint.lua
+++ b/steps/waypoint.lua
@@ -45,7 +45,7 @@ missions.register_step({
 
 		if stepdata.pos then
 			local distance = vector.distance(pos, stepdata.pos)
-			name = name .. "Position(" .. stepdata.pos.x .. "/" .. 
+			name = name .. "Position(" .. stepdata.pos.x .. "/" ..
 				stepdata.pos.y .. "/" .. stepdata.pos.z ..") " ..
 				"Distance: " .. math.floor(distance) .. " m"
 		end
@@ -141,10 +141,9 @@ missions.register_step({
 	on_step_interval = function(ctx)
 		local player = ctx.player
 		local stepdata = ctx.step.data
-
 		local pos = player:get_pos()
 
-		local distance = vector.distance(player:get_pos(), stepdata.pos)
+		local distance = vector.distance(pos, stepdata.pos)
 		if distance < stepdata.radius then
 			ctx.on_success()
 		end
diff --git a/ui.lua b/ui.lua
index 8c75347..084ed08 100644
--- a/ui.lua
+++ b/ui.lua
@@ -9,7 +9,7 @@ unified_inventory.register_page("missions", {
 			"label[1,0;Missions]";
 
 		if mission then
-			formspec = formspec .. 
+			formspec = formspec ..
 				"label[1,1;" .. mission.name .. "]" ..
 				"button[1,2;4,1;abort_mission;Abort mission]";
 		else
@@ -36,4 +36,4 @@ minetest.register_on_player_receive_fields(function(player, formname, fields)
 		local player_name = player:get_player_name()
 		missions.abort(player_name)
 	end
-end)
\ No newline at end of file
+end)