In short: Watch it for the pew pew, not the blah blah or wah wah. In long: Aldnoah zero season 2 really picked up in terms of combat and visual impact. The combat was very enjoyable to watch but alike its predecessor, the story and characters kind of lacked substance. It seems that the writers were trying to evoke emotions out of Slaine, but you really just don't care enough about the story to feel empathy. There's nothing thought provoking about this season either, so you're really just here for the soundtrack and combat.