The trailer was captured entirely in-game, during actual missions/levels (but with the GUI hidden of course) so you are seeing the actual graphics quality on display without any shenanigans. There are some pre-rendered cinematics in the game, but those play while mission levels are loading and relate some of the story.
The game maps are entirely 3d (as in X-Y-Z axis, not just a 2d plane) and each level is "self contained" around a theme but split into multiple "sectors" with wormholes and warpgates that take you between them. Sometimes these gates are heavily guarded, sometimes not and sometimes YOU have to stop enemies from using them. Mission objectives (both primary and secondary) take place across several sectors, so you might have one group scouting ahead and another defending another. One rather unique thing is that many levels are FULL of stuff... space is no longer just big and empty. A couple levels even take place with you flying around inside mega-structures or asteroids...