My wife and I went on this and had no idea, like yourself what it was all about. We queued with mainly teenagers and I thought, this was going to be pants - but, how wrong we were!
It's actually quite good and definitely worth it because it's so different and yes, at times the 10 minute show does occasionally get dark and if you don't mind bouncing up and down in your ride chair and getting slightly wet - then I recommend it. If not - don't bother.