Allows gamemaker to open up more than one instances of your game when compiling. Useful when testing networking projects that require a client and server object.
I take no credit for the code just posting for convenience. Allows multiple instances of your game to load on compile, simply add the 'obj_dual_instance' to the first room of your game.
Change the 'NumberOfChildren' variable within the dual instance object to define how many instances of your game should open.