diff --git a/src/ecs.lua b/src/ecs.lua
index fa585fa..9b72e6f 100644
--- a/src/ecs.lua
+++ b/src/ecs.lua
@@ -1,16 +1,16 @@
 ecs = {}
 
-local ALL_ENTITIES = {}
+local allEntities <const> = {}
 
 ---@alias System { callback: fun(delta: number, entity: any, a: any, b: any, c: any, d: any, e: any, any), shapes: {}, keys: string[], entityCache: nil | table<any, boolean> }
 
 ---@type System[]
-local SYSTEMS = {}
+local systems <const> = {}
 
 -- TODO: Add entity to any existing systems
 function ecs.addEntity(entity)
-	ALL_ENTITIES[entity] = true
-	for _, system in pairs(SYSTEMS) do
+	allEntities[entity] = true
+	for _, system in pairs(systems) do
 		if entityMatchesShapes(entity, system.shapes) then
 			system.entityCache[entity] = true
 		else
@@ -20,17 +20,17 @@ function ecs.addEntity(entity)
 end
 
 function ecs.removeEntity(entity)
-	ALL_ENTITIES[entity] = nil
-	for _, system in pairs(SYSTEMS) do
+	allEntities[entity] = nil
+	for _, system in pairs(systems) do
 		system.entityCache[entity] = nil
 	end
 end
 
-local PLACEHOLDER = {}
+local Placeholder = {}
 ---@generic T
 ---@return T
 function ecs.field()
-	return PLACEHOLDER
+	return Placeholder
 end
 
 function allKeysIncluded(entity, filter)
@@ -84,7 +84,7 @@ function tprint(tbl, indent)
 end
 
 function addSystem(callback, keys, shapes)
-	SYSTEMS[#SYSTEMS + 1] = {
+	systems[#systems + 1] = {
 		callback = callback,
 		keys = keys,
 		shapes = shapes,
@@ -99,10 +99,10 @@ end
 
 ---@param deltaSeconds number
 function ecs.update(deltaSeconds)
-	for _, system in pairs(SYSTEMS) do
+	for _, system in pairs(systems) do
 		if not system.entityCache then
 			system.entityCache = {}
-			for entity, _ in pairs(ALL_ENTITIES) do
+			for entity, _ in pairs(allEntities) do
 				if entityMatchesShapes(entity, system.shapes) then
 					system.entityCache[entity] = true
 				end
diff --git a/src/utils.lua b/src/utils.lua
index 712cc11..45f7f21 100644
--- a/src/utils.lua
+++ b/src/utils.lua
@@ -102,20 +102,20 @@ function getNearestOf(array, x, y, extraCondition)
 	return nearest, nearestDistance
 end
 
-local NO_VALUE = {}
+local NoValue <const> = {}
 
 function buildCache(fetcher)
 	local cacheData = {}
 	return {
 		cacheDate = cacheData,
 		get = function(key)
-			if cacheData[key] == NO_VALUE then
+			if cacheData[key] == NoValue then
 				return nil
 			end
 			if cacheData[key] ~= nil then
 				return cacheData[key]
 			end
-			cacheData[key] = fetcher(key) or NO_VALUE
+			cacheData[key] = fetcher(key) or NoValue
 			return cacheData[key]
 		end,
 	}