diff --git a/Libraries/Fusion/Animation/Spring.luau b/Libraries/Fusion/Animation/Spring.luau
index 5b0744f..e11a5c8 100644
--- a/Libraries/Fusion/Animation/Spring.luau
+++ b/Libraries/Fusion/Animation/Spring.luau
@@ -14,7 +14,7 @@ local SpringScheduler = require "../Animation/SpringScheduler"
 local updateAll = require "../State/updateAll"
 local xtypeof = require "../Utility/xtypeof"
 local peek = require "../State/peek"
-local typeof = require "../Polyfill/typeof"
+local typeof = require "../../../Modules/Polyfill/typeof"
 
 local class = {}
 
diff --git a/Libraries/Fusion/Animation/Tween.luau b/Libraries/Fusion/Animation/Tween.luau
index 5bd62a8..2240ce8 100644
--- a/Libraries/Fusion/Animation/Tween.luau
+++ b/Libraries/Fusion/Animation/Tween.luau
@@ -13,7 +13,7 @@ local logError = require "../Logging/logError"
 local logErrorNonFatal = require "../Logging/logErrorNonFatal"
 local xtypeof = require "../Utility/xtypeof"
 local peek = require "../State/peek"
-local typeof = require "../Polyfill/typeof"
+local typeof = require "../../../Modules/Polyfill/typeof"
 
 local class = {}
 
diff --git a/Libraries/Fusion/Animation/getTweenRatio.luau b/Libraries/Fusion/Animation/getTweenRatio.luau
index 8ec5aac..859f5a7 100644
--- a/Libraries/Fusion/Animation/getTweenRatio.luau
+++ b/Libraries/Fusion/Animation/getTweenRatio.luau
@@ -6,7 +6,7 @@
 ]]
 
 -- local TweenService = game:GetService "TweenService"
-local easing = require "../Polyfill/easing"
+local easing = require "../../../Modules/Polyfill/easing"
 
 local function getTweenRatio(tweenInfo: TweenInfo, currentTime: number): number
 	local delay = tweenInfo.DelayTime
diff --git a/Libraries/Fusion/Animation/lerpType.luau b/Libraries/Fusion/Animation/lerpType.luau
index 5067588..2846692 100644
--- a/Libraries/Fusion/Animation/lerpType.luau
+++ b/Libraries/Fusion/Animation/lerpType.luau
@@ -10,7 +10,7 @@
 ]]
 
 local Oklab = require "../Colour/Oklab"
-local typeof = require "../Polyfill/typeof"
+local typeof = require "../../../Modules/Polyfill/typeof"
 
 local function lerpType(from: any, to: any, ratio: number): any
 	local typeString = typeof(from)
diff --git a/Libraries/Fusion/Instances/Children.luau b/Libraries/Fusion/Instances/Children.luau
index 68d32aa..8cf161b 100644
--- a/Libraries/Fusion/Instances/Children.luau
+++ b/Libraries/Fusion/Instances/Children.luau
@@ -11,7 +11,7 @@ local logWarn = require "../Logging/logWarn"
 local Observer = require "../State/Observer"
 local peek = require "../State/peek"
 local isState = require "../State/isState"
-local typeof = require "../Polyfill/typeof"
+local typeof = require "../../../Modules/Polyfill/typeof"
 
 type Set<T> = { [T]: boolean }
 
diff --git a/Libraries/Fusion/Instances/OnChange.luau b/Libraries/Fusion/Instances/OnChange.luau
index 1960848..2abab9a 100644
--- a/Libraries/Fusion/Instances/OnChange.luau
+++ b/Libraries/Fusion/Instances/OnChange.luau
@@ -7,7 +7,7 @@
 
 local PubTypes = require "../PubTypes"
 local logError = require "../Logging/logError"
-local typeof = require "../Polyfill/typeof"
+local typeof = require "../../../Modules/Polyfill/typeof"
 
 local function OnChange(propertyName: string): PubTypes.SpecialKey
 	local changeKey = {}
diff --git a/Libraries/Fusion/Instances/OnEvent.luau b/Libraries/Fusion/Instances/OnEvent.luau
index ecd54b2..9350f19 100644
--- a/Libraries/Fusion/Instances/OnEvent.luau
+++ b/Libraries/Fusion/Instances/OnEvent.luau
@@ -7,7 +7,7 @@
 
 local PubTypes = require "../PubTypes"
 local logError = require "../Logging/logError"
-local typeof = require "../Polyfill/typeof"
+local typeof = require "../../../Modules/Polyfill/typeof"
 
 local function getProperty_unsafe(instance: Instance, property: string)
 	return (instance :: any)[property]
diff --git a/Libraries/Fusion/Instances/applyInstanceProps.luau b/Libraries/Fusion/Instances/applyInstanceProps.luau
index 0e554bd..1b891af 100644
--- a/Libraries/Fusion/Instances/applyInstanceProps.luau
+++ b/Libraries/Fusion/Instances/applyInstanceProps.luau
@@ -20,7 +20,7 @@ local xtypeof = require "../Utility/xtypeof"
 local logError = require "../Logging/logError"
 local Observer = require "../State/Observer"
 local peek = require "../State/peek"
-local typeof = require "../Polyfill/typeof"
+local typeof = require "../../../Modules/Polyfill/typeof"
 
 local function setProperty_unsafe(
 	instance: Instance,
diff --git a/Libraries/Fusion/Logging/logError.luau b/Libraries/Fusion/Logging/logError.luau
index 49f7323..c6b2878 100644
--- a/Libraries/Fusion/Logging/logError.luau
+++ b/Libraries/Fusion/Logging/logError.luau
@@ -20,24 +20,20 @@ local function logError(messageID: string, errObj: Types.Error?, ...)
 	local errorString
 	if errObj == nil then
 		errorString = string.format(
-			"[Fusion] " .. formatString .. "\n(ID: " .. messageID .. ")",
-			...
+			string.format(`[Fusion] {formatString}\n(ID: {messageID})`, ...)
 		)
 	else
 		formatString =
-			formatString:gsub("ERROR_MESSAGE", tostring(errObj.message))
+			string.gsub(formatString, "ERROR_MESSAGE", tostring(errObj.message))
 		errorString = string.format(
-			"[Fusion] "
-				.. formatString
-				.. "\n(ID: "
-				.. messageID
-				.. ")\n---- Stack trace ----\n"
-				.. tostring(errObj.trace),
+			`[Fusion] {formatString}\n(ID: {messageID})\n---- Stack trace ----\n{tostring(
+				errObj.trace
+			)}`,
 			...
 		)
 	end
 
-	error(errorString:gsub("\n", "\n    "), 0)
+	error(string.gsub(errorString, "\n", "\n    "), 0)
 end
 
 return logError
diff --git a/Libraries/Fusion/Logging/logErrorNonFatal.luau b/Libraries/Fusion/Logging/logErrorNonFatal.luau
index 9d59733..aedc120 100644
--- a/Libraries/Fusion/Logging/logErrorNonFatal.luau
+++ b/Libraries/Fusion/Logging/logErrorNonFatal.luau
@@ -19,18 +19,16 @@ local function logErrorNonFatal(messageID: string, errObj: Types.Error?, ...)
 
 	local errorString
 	if errObj == nil then
-		errorString =
+		errorString = string.format(
 			string.format(`[Fusion] {formatString}\n(ID: {messageID})`, ...)
+		)
 	else
 		formatString =
-			formatString:gsub("ERROR_MESSAGE", tostring(errObj.message))
+			string.gsub(formatString, "ERROR_MESSAGE", tostring(errObj.message))
 		errorString = string.format(
-			"[Fusion] "
-				.. formatString
-				.. "\n(ID: "
-				.. messageID
-				.. ")\n---- Stack trace ----\n"
-				.. tostring(errObj.trace),
+			`[Fusion] {formatString}\n(ID: {messageID})\n---- Stack trace ----\n{tostring(
+				errObj.trace
+			)}`,
 			...
 		)
 	end
diff --git a/Libraries/Fusion/Logging/messages.luau b/Libraries/Fusion/Logging/messages.luau
index 0a8ebea..6e218ed 100644
--- a/Libraries/Fusion/Logging/messages.luau
+++ b/Libraries/Fusion/Logging/messages.luau
@@ -23,6 +23,7 @@ return {
 	forKeysKeyCollision = "ForKeys should only write to output key '%s' once when processing key changes, but it wrote to it twice. Previously input key: '%s'; New input key: '%s'",
 	forKeysDestructorError = "ForKeys destructor error: ERROR_MESSAGE",
 	forPairsDestructorError = "ForPairs destructor error: ERROR_MESSAGE",
+	-- logError(invalidEasingStyle, easingStyle)
 	forPairsKeyCollision = "ForPairs should only write to output key '%s' once when processing key changes, but it wrote to it twice. Previous input pair: '[%s] = %s'; New input pair: '[%s] = %s'",
 	forPairsProcessorError = "ForPairs callback error: ERROR_MESSAGE",
 	forValuesProcessorError = "ForValues callback error: ERROR_MESSAGE",
@@ -49,7 +50,4 @@ return {
 	unrecognisedChildType = "'%s' type children aren't accepted by `[Children]`.",
 	unrecognisedPropertyKey = "'%s' keys aren't accepted in property tables.",
 	unrecognisedPropertyStage = "'%s' isn't a valid stage for a special key to be applied at.",
-
-	invalidEasingStyle = "The easing style must be a valid Enum.EasingStyle or a string of 'Linear', 'Quad', 'Cubic', 'Quart', 'Quint', 'Sine', 'Exponential', 'Circular', 'Elastic', 'Back', 'Bounce'. (got %s)",
-	invalidEasingDirection = "The easing direction must be a valid Enum.EasingDirection or a string of 'In', 'Out', 'InOut', 'OutIn'. (got %s)",
 }
diff --git a/Libraries/Fusion/MercuryExternal.luau b/Libraries/Fusion/MercuryExternal.luau
index b6e9b4b..4a9c412 100644
--- a/Libraries/Fusion/MercuryExternal.luau
+++ b/Libraries/Fusion/MercuryExternal.luau
@@ -1,6 +1,6 @@
 --!strict
 --[[
-    Roblox implementation for Fusion's abstract scheduler layer.
+    Mercury implementation for Fusion's abstract scheduler layer.
 ]]
 
 local RunService = game:GetService "RunService"
@@ -24,7 +24,7 @@ function MercuryExternal.doTaskDeferred(resume: () -> ())
 end
 
 --[[
-    Sends an update step to Fusion using the Roblox clock time.
+    Sends an update step to Fusion using the Mercury clock time.
 ]]
 local function performUpdateStep()
 	External.performUpdateStep(time())
@@ -38,7 +38,7 @@ function MercuryExternal.startScheduler()
 	if stopSchedulerFunc ~= nil then
 		return
 	end
-	-- if RunService:IsClient() then
+	-- if not _SERVER then
 	-- In cases where multiple Fusion modules are running simultaneously,
 	-- -- this prevents collisions.
 	-- local id = "FusionUpdateStep_" .. HttpService:GenerateGUID()
diff --git a/Libraries/Fusion/PubTypes.luau b/Libraries/Fusion/PubTypes.luau
index 6a1a3ff..90c5f36 100644
--- a/Libraries/Fusion/PubTypes.luau
+++ b/Libraries/Fusion/PubTypes.luau
@@ -133,7 +133,7 @@ export type Spring<T> = StateObject<T> & Dependent & {
 -- An object which can listen for updates on another state object.
 export type Observer = Dependent & {
 	kind: "Observer",
-	onChange: (Observer, callback: () -> ()) -> (() -> ()),
+	onChange: (Observer, callback: () -> ()) -> () -> (),
 }
 
 --[[
diff --git a/Libraries/Fusion/Types.luau b/Libraries/Fusion/Types.luau
index 8470b30..de8fb7f 100644
--- a/Libraries/Fusion/Types.luau
+++ b/Libraries/Fusion/Types.luau
@@ -83,7 +83,7 @@ export type ForPairs<KI, VI, KO, VO, M> = PubTypes.ForPairs<KO, VO> & {
 -- A state object whose value is derived from other objects using a callback.
 export type ForKeys<KI, KO, M> = PubTypes.ForKeys<KO, any> & {
 	_oldDependencySet: Set<PubTypes.Dependency>,
-	_processor: (PubTypes.Use, KI) -> (KO),
+	_processor: (PubTypes.Use, KI) -> KO,
 	_destructor: (KO, M?) -> (),
 	_inputIsState: boolean,
 	_inputTable: PubTypes.CanBeState<{ [KI]: KO }>,
@@ -103,7 +103,7 @@ export type ForKeys<KI, KO, M> = PubTypes.ForKeys<KO, any> & {
 -- A state object whose value is derived from other objects using a callback.
 export type ForValues<VI, VO, M> = PubTypes.ForValues<any, VO> & {
 	_oldDependencySet: Set<PubTypes.Dependency>,
-	_processor: (PubTypes.Use, VI) -> (VO),
+	_processor: (PubTypes.Use, VI) -> VO,
 	_destructor: (VO, M?) -> (),
 	_inputIsState: boolean,
 	_inputTable: PubTypes.CanBeState<{ [VI]: VO }>,
diff --git a/Libraries/Fusion/Utility/cleanup.luau b/Libraries/Fusion/Utility/cleanup.luau
index b67c299..9dc5a17 100644
--- a/Libraries/Fusion/Utility/cleanup.luau
+++ b/Libraries/Fusion/Utility/cleanup.luau
@@ -11,7 +11,7 @@
 	- an array - `cleanup` will be called on each item
 ]]
 
-local typeof = require "../Polyfill/typeof"
+local typeof = require "../../../Modules/Polyfill/typeof"
 
 local function cleanupOne(task: any)
 	local taskType = typeof(task)
diff --git a/Libraries/Fusion/Utility/needsDestruction.luau b/Libraries/Fusion/Utility/needsDestruction.luau
index 1ee6eb0..6e265b7 100644
--- a/Libraries/Fusion/Utility/needsDestruction.luau
+++ b/Libraries/Fusion/Utility/needsDestruction.luau
@@ -5,7 +5,7 @@
     requires manual cleanup.
 ]]
 
-local typeof = require "../Polyfill/typeof"
+local typeof = require "../../../Modules/Polyfill/typeof"
 
 local function needsDestruction(x: any): boolean
 	return typeof(x) == "Instance"
diff --git a/Libraries/Fusion/Utility/xtypeof.luau b/Libraries/Fusion/Utility/xtypeof.luau
index 19187f1..438dcf2 100644
--- a/Libraries/Fusion/Utility/xtypeof.luau
+++ b/Libraries/Fusion/Utility/xtypeof.luau
@@ -6,7 +6,7 @@
 	Otherwise, returns `typeof()` the argument.
 ]]
 
-local typeof = require "../Polyfill/typeof"
+local typeof = require "../../../Modules/Polyfill/typeof"
 
 local function xtypeof(x: any)
 	local typeString = typeof(x)
diff --git a/Libraries/Fusion/init.luau b/Libraries/Fusion/init.luau
index 43ac0e8..ebb7dcb 100644
--- a/Libraries/Fusion/init.luau
+++ b/Libraries/Fusion/init.luau
@@ -42,8 +42,8 @@ local Fusion = restrictRead("Fusion", {
 	doNothing = require "./Utility/doNothing",
 	peek = require "./State/peek",
 
-	typeof = require "./Polyfill/typeof",
-	TweenInfo = require "./Polyfill/TweenInfo",
+	typeof = require "../../Modules/Polyfill/typeof",
+	TweenInfo = require "../../Modules/Polyfill/TweenInfo",
 
 	Help = function()
 		return "See https://elttob.uk/Fusion/0.3/ for more information."
@@ -69,10 +69,10 @@ type Fusion = {
 
 	New: (
 		className: string
-	) -> ((propertyTable: PubTypes.PropertyTable) -> Instance),
+	) -> (propertyTable: PubTypes.PropertyTable) -> Instance,
 	Hydrate: (
 		target: Instance
-	) -> ((propertyTable: PubTypes.PropertyTable) -> Instance),
+	) -> (propertyTable: PubTypes.PropertyTable) -> Instance,
 	Ref: PubTypes.SpecialKey,
 	Cleanup: PubTypes.SpecialKey,
 	Children: PubTypes.SpecialKey,
diff --git a/Libraries/Fusion/Polyfill/TweenInfo.luau b/Modules/Polyfill/TweenInfo.luau
similarity index 77%
rename from Libraries/Fusion/Polyfill/TweenInfo.luau
rename to Modules/Polyfill/TweenInfo.luau
index 1ffb808..23ca5f2 100644
--- a/Libraries/Fusion/Polyfill/TweenInfo.luau
+++ b/Modules/Polyfill/TweenInfo.luau
@@ -1,7 +1,6 @@
 -- A basic polyfill for the TweenInfo.new function,
 -- allows using Enum.EasingStyle/Direction or strings instead
 
-local logError = require "../Logging/logError"
 local TweenInfo = {}
 
 function TweenInfo.new(
@@ -19,7 +18,7 @@ function TweenInfo.new(
 	-- convert it to a string
 	if type(easingStyle) ~= "string" then
 		if easingStyle then
-			easingStyle = tostring(easingStyle):gsub("Enum.%w+.", "")
+			easingStyle = string.gsub(tostring(easingStyle), "Enum.%w+.", "")
 		end
 	else
 		local ok
@@ -42,13 +41,17 @@ function TweenInfo.new(
 			end
 		end
 		if not ok then
-			logError("invalidEasingStyle", nil, easingStyle)
+			error(
+				`The easing style must be a valid Enum.EasingStyle or a string of 'Linear', 'Quad', 'Cubic', 'Quart', 'Quint', 'Sine', 'Exponential', 'Circular', 'Elastic', 'Back', 'Bounce'. (got {easingStyle})`,
+				0
+			)
 		end
 	end
 
 	if type(easingDirection) ~= "string" then
 		if easingDirection then
-			easingDirection = tostring(easingDirection):gsub("Enum.%w+.", "")
+			easingDirection =
+				string.gsub(tostring(easingDirection), "Enum.%w+.", "")
 		end
 	else
 		local ok
@@ -64,7 +67,10 @@ function TweenInfo.new(
 			end
 		end
 		if not ok then
-			logError("invalidEasingDirection", nil, easingDirection)
+			error(
+				`The easing direction must be a valid Enum.EasingDirection or a string of 'In', 'Out', 'InOut', 'OutIn'. (got {easingDirection})`,
+				0
+			)
 		end
 	end
 
@@ -99,9 +105,9 @@ function TweenInfo.new(
 			.. " Reverses:"
 			.. (reverses and "True" or "False")
 			.. " EasingDirection:"
-			.. easingDirection
+			.. tostring(easingDirection)
 			.. " EasingStyle:"
-			.. easingStyle
+			.. tostring(easingStyle)
 	end
 
 	mt.__metatable = "The metatable is locked"
diff --git a/Libraries/Fusion/Polyfill/easing.luau b/Modules/Polyfill/easing.luau
similarity index 100%
rename from Libraries/Fusion/Polyfill/easing.luau
rename to Modules/Polyfill/easing.luau
diff --git a/Libraries/Fusion/Polyfill/typeof.luau b/Modules/Polyfill/typeof.luau
similarity index 99%
rename from Libraries/Fusion/Polyfill/typeof.luau
rename to Modules/Polyfill/typeof.luau
index 170ab2c..faa9f2b 100644
--- a/Libraries/Fusion/Polyfill/typeof.luau
+++ b/Modules/Polyfill/typeof.luau
@@ -178,4 +178,5 @@ return function(value)
 			return t
 		end
 	end
+	return basicType
 end