Help with a levelling system?

This code has a lot of serious style problems.

• There is no need to use WaitForChild all over the place. Ensure they are loaded once at the beginning, and then just use ., it makes it much clearer -- using :WaitForChild implies that it might actually not be present, which just makes things more confusing.

• You probably shouldn't use coroutines the way you are. It would be clearer to just define normal functions and use spawn to start a new thread for them.

• You use game.Players.LocalPlayer a few times even though you have a variable for that.

• You don't use loops to fade transparency. This makes it much shorter and allows you to make it much smoother, too.

Here are all of the above problems cleaned up:

--by killerkill29

main = script.Parent
main:WaitForChild("total")
main:WaitForChild("level")
main:WaitForChild("cover")
main:WaitForChild("have")
main:WaitForChild("levelup")

player = game.Players.LocalPlayer

levelled = false

function checklevel()
    while wait() do -- what happens when exp == gained exp
        if main.total.total1.Value == main.have.have1.Value then
            main.level.level1.Value =  main.level.level1.Value + 1
            main.cover.levelnumber.Text = ("LEVEL " .. main.level.level1.Value)
            main.have.have1.Value = 0
            levelled = true
            print(player.Name .. " levelled up!")
            wait(1.4)
        end
    end
end

function level()
    while wait() do -- when the person levels up
        if levelled == true then
            main.levelup.Text = ("You are now level " .. main.level.level1.Value .. "!")
            char = player.Character
            char.Head.level.frame.Text = ("LEVEL " .. main.level.level1.Value)
            for transparency = 0.8, 0.2, -0.2 do
                main.levelup.TextTransparency = transparency
                main.levelup.TextStrokeTransparency = transparency
                wait(0.2)
            end
            for transparency = 0.4, 1, 0.2 do
                main.levelup.TextTransparency = transparency
                main.levelup.TextStrokeTransparency = transparency
                wait(0.2)
            end
            levelled = false
        end
    end
end

function levelfind()
    while wait() do --what happens when a person reaches a certain level
        char = player.Character
        if main.level.level1.Value == 10 then
            char.Head.level.frame.TextColor3 = Color3.new(0, 255, 0)
            char.Head.level.frame.TextStrokeColor3 = Color3.new(0, 0, 0)
        elseif main.level.level1.Value == 20 then
            char.Head.level.frame.TextColor3 = Color3.new(170, 255, 0)
            char.Head.level.frame.TextStrokeColor3 = Color3.new(0, 0, 0)
        elseif main.level.level1.Value == 30 then
            char.Head.level.frame.TextColor3 = Color3.new(0, 255, 255)
            char.Head.level.frame.TextStrokeColor3 = Color3.new(0, 0, 0)
        elseif main.level.level1.Value == 40 then
            char.Head.level.frame.TextColor3 = Color3.new(0, 0, 255)
            char.Head.level.frame.TextStrokeColor3 = Color3.new(255, 255, 255)
        elseif main.level.level1.Value == 50 then
            char.Head.level.frame.TextColor3 = Color3.new(255, 255, 0)
            char.Head.level.frame.TextStrokeColor3 = Color3.new(0, 0, 0)
        elseif main.level.level1.Value == 60 then
            char.Head.level.frame.TextColor3 = Color3.new(255, 170, 0)
            char.Head.level.frame.TextStrokeColor3 = Color3.new(0, 0, 0)
        elseif main.level.level1.Value == 70 then
            char.Head.level.frame.TextColor3 = Color3.new(255, 0, 255)
            char.Head.level.frame.TextStrokeColor3 = Color3.new(0, 0, 0)
        elseif main.level.level1.Value == 80 then
            char.Head.level.frame.TextColor3 = Color3.new(255, 0, 127)
            char.Head.level.frame.TextStrokeColor3 = Color3.new(0, 0, 0)
        elseif main.level.level1.Value == 90 then
            char.Head.level.frame.TextColor3 = Color3.new(255, 0, 0)
            char.Head.level.frame.TextStrokeColor3 = Color3.new(0, 0, 0)
        elseif main.level.level1.Value == 100 then
            char.Head.level.frame.TextColor3 = Color3.new(170, 0, 0)
            char.Head.level.frame.TextStrokeColor3 = Color3.new(0, 0, 0)
        elseif main.level.level1.Value <= 9 then
            char.Head.level.frame.TextColor3 = Color3.new(0, 0, 0)
            char.Head.level.frame.TextStrokeColor3 = Color3.new(255, 255, 255)
        end
    end
end


spawn(level)
spawn(checklevel)
spawn(levelfind)

Already looks less intimidating.

Now, we should definitely fix the final section.

An observation is that each one sets exactly the same two variables, and that it's just based on level1.Value being a multiple of ten. We'll use a list of the values instead of this thing.

Color3.new uses values between 0 and 1, not between 0 and 255.

One way to implement it would look like the following:

function levelfind()
    while wait() do --what happens when a person reaches a certain level
        char = player.Character
        local textColors = {
            [0] = Color3.new(0, 0, 0), -- 0
            Color3.new(0, 1, 0), -- 10
            Color3.new(2/3, 1, 0), -- 20
            Color3.new(0, 1, 1), -- 30
            -- etc
            -- etc
            -- etc
        }
        local strokeColors = {
            [0] = Color3.new(0, 0, 0), -- 0
            Color3.new(0, 0, 0), -- 10
            Color3.new(0, 0, 0), -- 20
            -- etc
            -- etc
            -- etc
        }

        local lev = math.floor( main.level.level1.Value / 10 )
        char.Head.level.frame.TextColor3 = textColors[ lev ]
        char.Head.level.frame.TextColor3 = strokeColors[ lev ]

    end
end

Now, looking at your problem.

You increase the level on line 17. In order to increase the level, the experience you have must exactly equal (==) the amount required.

Instead, use >= and decrease the amount you have by the amount you need (rather than setting to 0, because of overflowed points).

    while wait() do -- what happens when exp == gained exp
        if main.total.total1.Value >= main.have.have1.Value then
            main.level.level1.Value =  main.level.level1.Value + 1
            main.cover.levelnumber.Text = ("LEVEL " .. main.level.level1.Value)

            main.have.have1.Value = main.have.have1.Value - main.total.total1.Value
            -- I think this is the right thing to subtract by