Well...
Here's what I have a problem with:
Animation: Sometimes it just felt rough, it seemed either too vectored or just too rushed. Also the lip syncing wasn't up to par with what it seems you're going for. What I've noticed animators do is create several images of different mouth motions and then try to tie them into the scene. Meaning pre-fab the mouths and then add them in later with the audio.
Acting/Characters: I'm sorry but your characters screamed cliché at me. You have this dude with a DBZ hair-do who is tough and has powers he doesn't understand/completely control bringing up the whole "walking-weapon" deal that seems to be all over fiction these days. For an engaging character push the envelope a little bit, but not too much to the point the audience has no idea who they are. Meaning add something more to the agon with power rather than just control vs. chaos, it's been done to death. Also the token anime girl who is very friendly and dresses and acts like any other character. Conversely I hope you don't jump to the other extreme and have a total asshole girl who just likes to make people suffer for really lame reasons. Balance your characters between the extreme clichés and you might end up with a more unique cast.
Also to help your actors: tell them the emotions, have them get into their characters more before recording. Maybe have them act the scene with each other so that they can insert themselves into the part more and get your 'stage' direction as well as you do.
Plot Flow: It was really abrupt when the characters who the audience just began to attach themselves to after a few scenes got wasted (for all we know). It felt like a waste of time because all of a sudden you introduce another character WHILE creating the plot pitch WHILE removing the others ( maybe for a while I suppose). Slow the story down a bit, the world won't end tomorrow. The last thing you want to do is blast through what could be a neat story by cramming the plot too close together. If you do intend to keep the others alive somehow, it really would have helped to make a hint at that at the end, otherwise the movie feels incomplete. I know it looks like a series but each episode still needs a sense of unity of whatever magnitude. Unify you plot slightly (on a smaller scale) and you should be good.
This seems like it's your baby. I can relate I have one too. Which is why I don't want you guys to sabotage your potential by cutting corners. You really could make this better, but for the sake of a review, there is a lot of room for improvement.
Oh and PLEASE don't get the idea that I'm obsessed with originality, I'm not. I enjoy a nice diaspora of entertainment, artsy and simple alike. I just feel that you guys could be heading for a wall eventually and that you could make this flash series stand out more.
What I did like were the backgrounds, at one point I was reminded of the guy who made Waterlolies, so in that regard: good job!