I just watched a couple of times, now I think what may help you.
1- there are two parts in your trailer because the music stops in the middle, that makes me feel that there is a disconnection between the first part and the second when the music starts again, the pace is broken for me
2- when you start the second part with the cloud blue planet, I don't feel there is anything special to see there, there is no connection, I feel like you are showing different parts of your game but there is no cohesion, planets are nice, but usually people do not look at them that much in a trailer unless you show up the main actor of your game arriving from hyperspace for example, so you understand ah! I am getting there...
3- I like how it starts, but the pace is quite strange by the end, but once you go into the second part saying save the universe..etc.. the pace turns strange when you start showing all the other races and no words?, I am not quite sure how to tell you but makes me feel awkward.
maybe when you say in the first part befriend or survive hostile races you can show up some quick clip of the others? so you don't really know who are the good / bad ones, that leaves people to think and explore for later
4- gameplay is important to show, so people understand about your game, how you show it is up to you, but sometimes showing up some close ups to make your ships look more awesome makes bigger impact, there are just only very few portions in which I can see the ships, most of the other parts are from far away so it is difficult to see the ship, for you game I feel that your ship is the main actor, so show it in a glorious way.
Well these are my personal opinions and hope some of them help you, your game looks very good and I am looking to play it