You could be better at visual exposition.
Maybe there ought to be a special trailer portal where trailers can be submitted seperately from games and movies. Anyway, your trailer gets the job of publicity done, but it doesn't stand on its own as something interesting to watch. Conceptually it is very simple, without much visual exposition. All that you tell us is that an ICBM incineerates a city as a cloaked figure watches.
It would be more effective if you explored more angles and showed more dynamic movement. There is a fine line between creating suspense and simply compensating for lack of animation experience, and it looks like the latter. Take inspiration from Fallen Angel, a tried and true apocalypse story, even if you can't yet animate like that. An animator's job is to make things move. Even if you have the right music, the right text, you need to do your part of the project.