This is one of those anime where you should realize what the rest of the series is going to be like after watching the first episode, trust me, plot takes more action during the second half, but it's fundamentally the same. All in all I found it entertaining, but lacking enough that it's just average.
First, to consider the good aspects of this show...I would have to say animation and the slight differences there is than the normal mediocre shows of this genre. Yes, the animation and character design themselves was cute. The cute little girl with white hair and red eyes, and the 'main character' Sinon Asuna...whoops Jimon Asuta's little side braid and suit. Mabye nobody cares, but the side braid is actually sort of cute and I really don't see it often on main characters. Speaking of which, I didn't look into it or anything, but this animation is very similar to Sword art online's, and the main character reminded me of Kirito, though he was several levels less useful. The other characters various 'transform' outfits were cute, and if there was actually some serious team fight scenes, that would have been really cool/adorable. When it comes to slight variations from the norm, it would have to be the fact that they are technically aspiring to conquer the world, which was a slightly refreshing goal, even if they are still fundamentally good people. So CUTE CHARACTERS AND A SLIGHTLY REFRESHING PLOT GOAL was what was good about this Anime.
Problems with this show that made it fairly average. First off, completely predictable 'plot twists' and they don't REALLY think we're going to not know who's behind the masks right? I like to assume that producers do that sort of thing with the whole 'main character doesn't know who's behind the mask but it's actually his/her friend' completely out of plot convienience, and that they aren't actually trying to give us a plot twist...
Second, is the complete lack of seriousness. The show got slightly more serious towards the end, but it was filled with silly characters and unserious scenes with a seemingly whimsical and naiive mindset to conquer the world. Even the 'most serious' scenes didn't feel that important or moving because you know that it will soon go back to sillyness. Considering the plot, (aka conquering the world), it wouldn't have hurt to have a little more seriousness in exchange for the sillyness, or at least some more interesting fight scenes, (though we know the MC can't fight squat, the other characters would be interesting to watch).
The characters, (and this almost always happens with 12 episode shows) were underdeveloped. What you do see about some of the characters past's are vague and often not that helpful to developing the character's personality. Even towards the end, the character they could have at least done something to, considering he had his past explained as much as he needed to, was Asuta. Instead I felt like he barely did anything the entire time, other than agreeing to the plot status quo at one point and saying he would stay on the 'world conquering side', oh and being suprised. Other than that, he couldn't fight, and spent most of the show being timid and taking as little action as possible. Further more, the even more important main character Zvezda was left unexplained (technically Asuta is MC, but well, he's even less interesting) WHY IS SHE IMMORTAL?WHY DOES SHE WANT TO CONQUER THE WORLD? WHAT IS THAT DOLL WITH THE COMPLICATED NAME? And various other questions are left out with an 'watch the next season' or mabye they meant it to be 'read the manga' ending. *sighs*.
Sound was average, nothing stuck out to me at least, I guess the opening was so-so. But well, that's mainly personal opinion.
Though it was an overall entertaining action/comedy show with good animation, it carried many of the same flaws other 12 episode shows do, and therefore was lacking, and hits the line at slightly above average.