Help me, my GUI opener script doesn't work?

Ok, I am making a game, and have a GUI thats ment to open when a player walks on a part, and GUIopen is a bool value in the script.Parent.Value and it does get closed, in the GUI thats ment to open there a "Close" button that closes everything that was open and makes the GUIopen false.

debounce = false
GUIopen = script.Parent.Value

function onTouched(hit)
    local plr = game.Players:GetPlayerFromCharacter(hit.Parent)
    if plr and debounce == false then
		if GUIopen.Value == false then
       		debounce = true
       	 	GUIopen.Value = true
			wait(0.1)	
			plr:WaitForChild("PlayerGui").TeleportMenu.Background.Visible = true
        	plr:WaitForChild("PlayerGui").TeleportMenu.Background.Transparency = 1
			wait(0.1)
			plr:WaitForChild("PlayerGui").TeleportMenu.Background.Transparency = 0.9
			wait(0.1)
			plr:WaitForChild("PlayerGui").TeleportMenu.Background.Transparency = 0.8
			wait(0.1)	
			plr:WaitForChild("PlayerGui").TeleportMenu.Background.Transparency = 0.7
			wait(0.1)	
			plr:WaitForChild("PlayerGui").TeleportMenu.Background.Transparency = 0.6
			wait(0.1)	
			plr:WaitForChild("PlayerGui").TeleportMenu.Background.Transparency = 0.5
			wait(0.1)	
			plr:WaitForChild("PlayerGui").TeleportMenu.Background.Transparency = 0.4
			wait(0.1)	
			plr:WaitForChild("PlayerGui").TeleportMenu.Background.Transparency = 0.3
			wait(0.1)	
			plr:WaitForChild("PlayerGui").TeleportMenu.Background.Transparency = 0.2
			wait(0.1)	
			plr:WaitForChild("PlayerGui").TeleportMenu.Background.Transparency = 0.1
			wait(0.05)	
			plr:WaitForChild("PlayerGui").TeleportMenu.Frame.Visible = true
			wait(0.04)
			plr:WaitForChild("PlayerGui").TeleportMenu.Frame.Title.Visible = true
			wait(0.04)
			plr:WaitForChild("PlayerGui").TeleportMenu.Frame.MultiPlayerButton.Visible = true
			wait(0.04)
			plr:WaitForChild("PlayerGui").TeleportMenu.Frame.SinglePlayerButton.Visible = true
			wait(0.04)
			plr:WaitForChild("PlayerGui").TeleportMenu.Frame.BossPlayerButton.Visible = true
			wait(0.05)
			plr:WaitForChild("PlayerGui").TeleportMenu.Frame.BackButton.Visible = true
        	debounce = false
		end
    end
end

script.Parent.Touched:connect(onTouched)

So, the script works when I test it alone in studio, but when I got someone else to test in in-game in the roblox player heres what happens, It works for me when I step on it for the first time then it worked, the I got off, then the other player tried to step on it and it didn't work, and I tried again after him and it didn't work for me too.... Then, we both left, and we joined again, and I told the player to step on the part first this time, and he said it worked, so then he got off, and I tried then it didn't work for me, then he tried getting on it again and it didn't work... D: This is too messed up for me, please help?

Is this a server side script? If so you should be using a remote function/event so that all of the animation is done by the client and not the server as this will cause a lot of lag.

This script will not run again because of this line:-

GUIopen.Value = true

This will stop the script from running the next time as this will be true.

Hope this helps.