A good start, and I agree about the flaming crap on Atari. That's why I don't post anything at all over there until its done, and someone says its good enough to go over there.
Anyway, this is a good start. However, in the begining you launched up the same Firework six or seven times, the red one. If you changed it up, say had another one of a different type go up next to it that'd be great.
The Idea is great. The majority of people haven't been to grad nite, so they can't say "well that's not at all what its like" And I haven't been, and I won't be going
so no problems there.
The scenery around the castle looks pretty good, but the castle itself isn't looking as good. May I suggest some Custom scenery.
http://battor.77.free.fr/ferme.php Yes the site does say its closed, but the downloads still work.
That site has the "Chateau Magique V2"
It isn't the DLR castle, or the WDW castle, its a mix of all of the castles, and I know your doing DLR but this will look much better in its spot. You could even sink the castle into the ground a bit to make it look smaller. If you want to keep the castle "non cs" I understand, but you've gotta do better than that. I've seen people make there own and have it look good.
Also I know you were making a preview, but if you use the FCR (flying camera route) it'll make a great video. I've been taking video production classes for two years (soon to be three) and we are always told to make sure the picture moves, changes angles every 5-10 seconds to keep the audiences attention. But we all know RCT3 gamers have long attention spans :P but it still wouldn't hurt.
I look forward to seeing the final video.