It's your first movie on newgrounds...
is it your first movie ever? I don't mean to sound ruse by saying that but if it is ur first then great, keep up the good work, if not then maybe a few things could be sorted.
Firstly, this is supposed to be a trailer right? Well the thing is about trailers is that they include shots from the movie, putting up the movie what has been made so far as the trailer wasn't the best thing that could have been done.
Next try and add a few more sounds, you can get all sorts from the web, the best places are usually stated at the end of most animations in the credits, it doesn't take too much more effort to add appropriate sounds to a movie.
And last, try and keep the backing music going as alot have stated, try fading it in and out if not.
Other than those slight things, the movie could be fairly enjoyable i think.
Keep it up and hopefully you'll get a good reception with this when you post the full movie.