Meh
Sure it was the opener and story had to be done. But didn't you feel like everything was very rushed in the story? There was alot of introduction without much explanation as to why or what motivation any character had. Obviously the next episode is going to revolve around this new character, but just make sure to keep things to a minimum. You've got the entire series to reveal background stories and such. There's no reason the entire outline of the character has to be made right away.
As for the story itself, I feel like I've seen this before. Do something new to spice things up. A betrayal somewhere in the ranks would be a great start.
Otherwise, the art was okay. Sprites zoomed in on can look good if they have the right background. Otherwise it just gets messy and very blocky.
Good luck with the next one, hope you take some of my advice.