The best thing I liked about this series is the unique fantasy world it's set in. As a gamer since childhood, the title itself was enough to capture all my attention to this anime, and watching the first few minutes, I got all worked up about it. A world where even wars are settled with games.! It might not seem that hard of an idea to come up with, but I am pretty sure I've never seen something like it in any actual anime or film before.
Another strength point is the characters. Imho, most animes tend usually to have quite similar frequent characters, which you could predict all their reactions really easily. I won't say that ALL characters in this series are exceptions, actually, they're mostly not. However, the two protagonists (I suppose we should assume they're always together!), are strong exceptions. More particularly, Sora is one of the rare inspiring anime characters I've seen lately, I'd say he's a lot like Yagami Light from deathnote, and I really love that!
On the other hand, I think the plot could have been much more into game than it's at the moment. I haven't read manga and the series didn't depict much of it yet, but so far, I didn't actually feel it's that much of a game world. Well, other than the fact that it's a world where all conflicts are resolved with games, there's basically no much signs of video games within the series. I mean, I think it would've been way more fun if the general themes were more deeply set into a gaming world. Like; scenarios, animation, and drawing styles could all be possibly altered to reflect a game-based world, and I am sure I was going to enjoy that a lot.
Also, as much as it's frustrating, the art is actually weak. I like the coloring style, but it sometimes makes it hard to distinguish things clearly. I am pretty sure graphics could have been a lot better. Still, they're fine more or less.
It's not one of the best anime series ever made, but most definitely, it's unique and so damn fun.
