Just finished the demo, getting an S in all of the 5 levels and... It's incredible, I really enjoyed and liked it, especially the sound effects.
Shooting with the vulcan or the railcannon hits me like crack.
I think the missiles should be a bit more impactful, I mostly only used the primary weapons and the grenades while playing. It can be just me too.
Anyway, it's was an awesome experience, can't wait for the full game.