Expected '=', got 'end' Error?

Errors

In your script you made a function a Variable which won't work, you also added game.Players.Player.PlayerGui, player in this case, would be nil, because when you joined the server there would be no player so what would we do? We would use game.Players.LocalPlayer It finds the LocalPlayer which is you, But please note that LocalPlayer Only works in a LocalScript.

Perfections

local play=script.Parent
plr=game.Players.LocalPlayer
chr=plr.Character--the Character of the player(found in Workspace)
play.Text="HELLO"--Change
play.MouseButton1Down:connect(function()--functions don't make a good variable
	wait(.1)--or 0.1
	play.Text="You will respawn in 3 seconds"
	wait(3)
	plr.PlayerGui.ScreenGui:remove()--remove once clicked
	wait(.2)
	plr.CameraMaxZoomDistance=0.5
	plr.CameraMinZoomDistance=0.5
	chr.Humanoid.Died:connect(function()
		plr.CameraMaxZoomDistance=400
		plr.CameraMinZoomDistance=0.5
	end)
end)

Ok so what I've added here is your playgui/button, then the LocalPlayer that I was talking about earlier, as you can see I added plr.CameraMaxZoomDistance=0.5 instead of using game.StarterPlayer, its because StarterPlayer, sets it up before the player ever joins and when the server is running it can not be changed again(when on server). I added a chr.Humanoid.Died function so that it won't be in FPS mode when you respawn.

please note that this is in a LocalScript If there are any errors just Comment below.