Actually there is no way to loop a movie inside Slide-Effect.
Obviously, I understand the need for a feature like this.. let’s say for looped animated backgrounds… and I will put this feature on my todo list.
But I cannot promise anything because it is not that simple: It is, basically, a limitation of the graphical engine I use and the only way I can think of is to reload the movie when it is finished.. and it is not a very smart way to loop content… anyway I will take a deeper look into this.
If you are talking specifically about the water background, you can display it as long as you want, it is not limited at all.
Hope it helps.