Incomplete statement: expected assignment or a function call obby?

Your program contained syntax errors on lines 16-18. You also had several logic issues with you Script which were going to run you into a cesspool of semantic errors too. Please be careful when writing code.

Note:

It is also highly recommended not to to make :SetAsync() calls every time the ValueObject updates. You put your DataStore at high-risk for exhaustion problems. Since you're saving a single Value, it's not important to do so either, so just leave requests for PlayerLeaving.

You should also use :BindToClose() with DataStore's to compensate for abrupt server-shutdownts.

local DataStoreService = game:GetService("DataStoreService")
local myDataStore = DataStoreService:GetDataStore("MyDataStore")

local Players = game:GetService("Players")

Players.PlayerAdded:connect(function(Player)
    local Leaderstats = Instance.new("Folder")
    Leaderstats.Name = "leaderstats"
    Leaderstats.Parent= Player

    local Stage = Instance.new("IntValue")
    Stage.Name = "Stage"
    Stage.Value = 0
    Stage.Parent = leaderstats

    local Data;
    local Success, ErrorMessage = pcall(function()
        Data = myDataStore:GetAsync(Player.UserId.."-Stage")
    end)
    if (Success) then
        Stage.Value = Data
    else
        print("There was an error whilst getting your data!")
        warn(ErrorMessage)
    end
end)

Players.PlayerRemoving:Connect(function(Player)
    local Leaderstats = Player:FindFirstChild("Leaderstats")
    if (Leaderstats and Leaderstats.Stage) then
        local Stage = Leaderstats.Stage.Value
        local Success, ErrorMessage = pcall(function()  
            myDataStore:SetAsync(Player.UserId.."-Stage", Stage)
        end)
        if (Success) then
            print("Successfully saved data!")
        else
            print("There was an error whilst saving your data!")
            warn(ErrorMessage)
        end
    end
end)

game:BindToClose(function()
    for _,Player in pairs(Players:GetPlayers()) do
        Player:Kick() --// Force PlayerLeaving to fire
    end
end)

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