Let me just start this review by saying that this anime does a lot of things right. It starts off with an interesting hook and displays a beautiful and intricate world. The animation is fantastic and it has a killer opening that will keep you from skipping the intro. While watching I couldn't help feeling like this anime was kind of a throwback to Cowboy Bebop or Trigun. However, this doesn't display nearly the same quality in writing or polish as either of those shows. After the first couple of episodes the shiny animation and amazing soundtrack couldn't keep me from noticing the shows flaws. And as the show continued, these flaws became more egregious and severely hindered my enjoyment.
The first major flaw I noticed were the characters. While naive and upbeat characters aren't always annoying, Sam's persistent friendly attitude and innocent lack of situational awareness grates on my nerves. Mostly because it undercuts any potential tension that may have been there otherwise but also because there has to be a limit to not understanding when someone is trying to kill you and is not friendly. I don't care that it can be explained by saying that was how she was programmed, the point is that it gets incredibly annoying. Philly has the opposite problem, he is an arrogant and incompetent . I feel like you can either make a character a competent or someone who is incompetent but has redeeming qualities. Philly is neither and makes you question why you should care about his fate and what purpose he even serves for the story. Casey is probably the only character in the main cast I like and Prince Kelby is your typical sheltered annoying brat. Thankfully the side characters tend to have more interesting and likable personalities but we are stuck following Philly, Sam or Kelby most of the time.
The Second Flaw is the action. It is underwhelming and kind of disappointing. This is not helped by the fact that they often cut away from it and to something a lot less interesting. It's a pity since the intro has amazing looking action, however, it looks like they couldn't replicate the pace and intensity for the actual anime. Finally, the pacing for this anime is slow. There seems to be a lot of filler episodes that don't progress the plot and even within episodes there is a lot of empty space where not much happens. It seems like they were struggling to justify 12 episodes and had to drag out the story and runtime to match it. This is perplexing considering that the season ends on a cliffhanger.
All in all I would say that this anime is mediocre. It won't take priority over any shows you are currently watching but, if you find yourself lacking in good shows you could do worse than this one.