LocalScript Issue: The local script works in studio, but not in-game?

I know for a fact this is a 'LocalScript' issue, but I'm not quite sure how to adjust the script for it to function out of studio.

Here's the script:

local RANGE = 240
local TIMESTEP = 1 / 30
local SECONDS_BETWEEN_RECONSTRUCTION = 3
local MAX_DIST_RATIO = 0.84


-- Waits for parent.child to exist, then returns it
local function WaitForChild(parent, childName)
    assert(parent, "ERROR: WaitForChild: parent is nil")
    while not parent:FindFirstChild(childName) do parent.ChildAdded:wait() end
    return parent[childName]
end

-----------------
--| Variables |--
-----------------

local PlayersService = Game:GetService('Players')

local MyPlayer = PlayersService.LocalPlayer
local Camera = Workspace.CurrentCamera


local Radar = WaitForChild(Workspace, 'Radar')

local Radar_Gui = script.Parent
local RadarFrame = WaitForChild(Radar_Gui, 'RadarFrame')

local Background = WaitForChild(RadarFrame, 'Background')
local Border = WaitForChild(RadarFrame, 'Border')
local FoeBlip = WaitForChild(RadarFrame, 'FoeBlip')
local FriendBlip = WaitForChild(RadarFrame, 'FriendBlip')
local SelfBlip = WaitForChild(RadarFrame, 'SelfBlip')

-- Any names (keys) not in this list will be deleted (values must evaluate to true)
local SaveList = {Background = 1, Border = 1, FoeBlip = 1, FriendBlip = 1, SelfBlip = 1}

local ObjectToBlipTable = {}

local LastReconstructionTime = 0

local RunService = Game:GetService('RunService')


Background.Visible = true
Border.Visible = true
SelfBlip.Position = UDim2.new(0.5 - SelfBlip.Size.X.Scale / 2, 0, 0.5 - SelfBlip.Size.Y.Scale / 2, 0)

local function IsInRange(inversedFrame, pos)
    local pos = CFrame.new(pos.X, 0, pos.Z)
    local relativeCFrame = inversedFrame * pos
    local distanceRatio = relativeCFrame.p.Magnitude / RANGE
    return distanceRatio < MAX_DIST_RATIO, relativeCFrame
end

local function CheckLos()
    -- Uncomment the following to hide non-visible enemies that are far away
    --[[
    if distanceRatio >= 0.7 and player.TeamColor ~= MyPlayer.TeamColor and player.Character then
        local torso = MyPlayer.Character:FindFirstChild('Torso')
        local otherTorso = player.Character:FindFirstChild('Torso')
        local ray = Ray.new(torso.Position, (otherTorso.Position - torso.Position).unit * RANGE)
        local hit = Workspace:FindPartOnRay(ray, MyPlayer.Character)
        if not hit or hit.Parent ~= otherTorso.Parent then
            unit.Visible = false
        end
    end
    --]]
end

local function ConstructBlipTable()
    for _, object in pairs(Radar:GetChildren()) do
        if object:IsA('ObjectValue') and object.Value and object.Value:IsA('BasePart') then
            local pos = object.Value.CFrame.p
            local objGui
            for _, child in pairs(object:GetChildren()) do
                if child:IsA('Frame') then
                    objGui = child:Clone()
                    objGui.Parent = RadarFrame
                    ObjectToBlipTable[object.Value] = objGui
                end
            end
        end
    end

    for _, player in pairs(PlayersService:GetPlayers()) do
        if MyPlayer and player ~= MyPlayer and player.Character and player.Character:FindFirstChild('Torso') then
                unit = FriendBlip:Clone()
        else
                unit = FoeBlip:Clone()
        end
            unit.Visible = false
            unit.Name = player.Name
            unit.Parent = RadarFrame
            ObjectToBlipTable[player.Character.Torso] = unit
        end
    end


local function ReconstructBlipTable()
    -- Destroy anything in the frame that isn't going to be updated
    for _, label in pairs(RadarFrame:GetChildren()) do
        if not SaveList[label.Name] then
            label:Destroy()
        end
    end
    ObjectToBlipTable = {}
    ConstructBlipTable()
end

local function UpdateRadar()
    local frame = Vector3.new(Camera.CoordinateFrame.x, 0, Camera.CoordinateFrame.z)
    local focus = Vector3.new(Camera.Focus.x, 0, Camera.Focus.z)
    local frame = CFrame.new(focus, frame)
    local inversedFrame = frame:inverse()

    for obj, objGui in pairs(ObjectToBlipTable) do
        if obj then
            local pos = obj.CFrame.p
            if pos and objGui then
                local isClose, relativeCFrame = IsInRange(inversedFrame, pos)
                if isClose then
                    local xScale = 0.5 - ((relativeCFrame.x / RANGE) / 2) - objGui.Size.X.Scale / 2
                    local yScale = 0.5 - ((relativeCFrame.z / RANGE) / 2) - objGui.Size.Y.Scale / 2
                    objGui.Position = UDim2.new(xScale, 0, yScale, 0)
                    objGui.Visible = true
                else
                    objGui.Visible = false
                end
            end
        -- if there is no obj but a gui for it
        elseif objGui then
            objGui.Visible = false
        end
    end
end



while true do
    local now = tick()
    if tick() - LastReconstructionTime > SECONDS_BETWEEN_RECONSTRUCTION then
        ReconstructBlipTable()
        LastReconstructionTime = now
    end
    UpdateRadar()
    wait(TIMESTEP)
end

It's a LocalScript inside a ScreenGUI that's in the StarterGUI. The ScreenGUI also has a frame with ImageLabels in it.