Ive seen games where they send you to different games without having the loading thing in the bottom right corner and the name. How do they do it?
You sir, are in luck, what you're asking is very easy to do, for the Teleport() function has an option to take away the default loading screen.
local gui = SomeScreenGuiThatYouWantToUseAsALoadingScreen game:GetService('TeleportService'):Teleport(1818, game.Players.Telamon,"Teleportin", gui)
For more information on custom loading screens with TeleportService, read the wiki article about it.