I'm pretty disappointed by the video. I didn't really have any expectations but I still think it looks like a badly paced ride with one or two cool effects.
I could live with the lighting or the fact that it might be a little rushed (like most darkrides), but I have four main problems with what I saw:
1. I can't help but feel that apart from the trademark red hair it doesn't look at all like Ariel. She looks more like a disturbing hybrid between princess baby Ariel and Chucky.
2. In the "Under the sea" scene, as you go under the arch your attention is directed up towards the characters on top of it, inevitably exposing the brightly lit factory-like ceiling and hundreds of ugly spotlights shining into your eyes.
3. The 3-D scenes... WHY???
4. As someone else mentioned, the story makes absolutely and positively no sense at all for those not familiar with the movie.
I hope I'll have a completely different experience once I actually ride it but I'm not keeping my hopes up.