Well looking at the hints in the theme etc.....
They said there are various elements that will play with the riders, distract them and change our emotions. I am not really sure what props stuck to the Marmaliser Legs or the Screen will actually do to distract us at all, i have been on rides with such things and even basic rides with such things, such as the Ducks on the Water Ride.. In Florida there are many rides with things at the side of the tracks and themes, and on the rides that go really fast they dont have such things as u hardly notice them.
I think the whole idea is to create fear and tension and to mentally play with your mind, maybe this can be done before you get onto the trains.
Going back to interaction, and while your on any kind of ride, having something that sprays you with Water certainly adds a extra experience to the Ride rather than visual elements. Look at the Rabid Rides, take away the Water and well whats the point, the getting Wet is what makes this Ride.
I have been on various Rides in the USA, and seen Projection Mapping and its neat but only works on rides in he dark and that are not fast, as with other visual elements.
Some rides have added elements that add to the ride, some blast you with ice cold gas that makes you cold, and then some have real fire balls above you that you can feel the intense heat, some the train wobbles and bounces about and some yes you get water sprayed on you and all these add to the ride.
Maybe the Smiler will have something similar maybe not, we just cant be sure, what is for certain is some of these interactive kinds of events, can distract you from the ride, so while you may be pooping your self on the ride a spray of water can make you giggle and for that moment distract you from the traditional thrill of a Roller Coaster.
Again though, while the Marketing could hint to maybe some elements like this, so far no video has proven any such thing to be the case, however for purposes of testing and reporters, such things could be simply turned off until open day.
I do think there is more to this ride experience but that does not mean that anything more is added to the actual track and while you ride along that track, apart from maybe what purpose does the screens and cameras and speakers have on the Vertical Lift Hill.
And in which way could they play anything on regards to a Worlds First?