The anime looks and sounds great. The art is solid; the characters and demons look exactly as they do in the game and the animation is never not satisfying in the action sequences. The voice actors all fit the characters, who were unvoiced in the game, well. Nothing too jarring. The music doesn't do anything wrong and the OP and ED are both pleasant if not overwhelmingly memorable.
The story and the characters are where it falters some, and it's largely because it has too much to do in too little time. The game on which it's based is a 50 or so plus hour RPG that takes multiple playthroughs to explore everything. To fit it all into 13 24 minute episodes means gutting out so much of the build up and character development that the game had going for it. This makes the characters seem rather lifeless compared to how energetic and enjoyable they are in the game and also limits the scope of the story some. Devil Survivor 2 could be a surprisingly lighthearted and often humorous game, something that made the stark revelations about the fate of the world and characters hold more gravity. Without the time to build all that, the story becomes somewhat deflating. It's just not as much fun as it should be.
I love the characters in Devil Survivor 2, and seeing them fully animated is a lot of fun. Without something like the Fate system in the game to develop them and make their bonds with the main character mean something, a lot of what makes them fun is left out though. It's not just that though; the anime changed a few things it probably shouldn't have. Joe, who is a part of the group since day one in the game and provides so much refreshing whimsy is reduced to a minor supporting role. Io seems completely different; she smiled a lot more and just came across as a lot less weak. Other characters who can get fully developed in the game are simply killed off prematurely.
Worst somehow is Hibiki though, surprisingly. He was your ordinary silent protagonist in the game, but how events unfolded did depend on how he acted. In my first playthrough he never missed an opportunity to joke around, was brash, aloof and quick to side with JP's. The anime version could be different from that though, and probably picked the worst way possible to play him, reducing him to your average mopey shounen protagonist. To make matters worse, the anime decided to make him more powerful than his friends and the other characters from the start. In the game, he and his friends are noticed because they're resourceful and because it's a Strategy RPG and he's able to use his intelligence to win difficult fights and become stronger for them. Having him become the focus from the start because he's "the one" seems much more hollow and moreover pushes his friends more out of focus than they should be, especially since they were the focus of the game.
All that said, the anime is certainly not torture for fans of the game. No, it's actually quite enjoyable to see all the familiar demons pop up and fight. It's especially satisfying to see how the very familiar Septentrion fights, the boss fights in the game, are handled. It's not difficult to enjoy the anime, even as I see where it goes wrong and some of the places where it decides to diverge from the game's story are interesting.
If you haven't played Devil Survivor 2, I would definitely recommend that over the anime. The anime on it own isn't bad though. For a non-fan, I'd probably deduct 1-3 points from my overall score, depending on tastes. The characters aren't going to come across as what they could be not having the time they needed to grow, and the same goes for a lot of the plot development. Still, there's a lot to like, I think. The animation is nice, the action satisfying and the core plot intriguing enough. I've yet to be bored with it at the least.
Update: Having seen the series to completion now, I had to dock a point from my initial score. I still think the anime looks great and has more than enough moments to justify a watch, but it really just kept making increasingly poor decisions in regards to story progression. There came a point where I found it harder to separate out the experience I had with the anime from that of the game and it cut into my overall enjoyment. Characters and even whole important themes and events from the game are discarded with increasing frequency just leaving it feeling fractured, while the mood is kept more grim than it needed to be, the amusing sequences of the game cut short, skipped over or drained of fun. Meanwhile, the cool stuff it does do slows down considerably--the last few Septentrion fights aren't as interesting or involving and for some reason the show decides to keep the number of unique demons we see in action very limited.
I said before that fans would enjoy this, but I don't know anymore. If you can effectively separate out the good experience of the game as you watch, the anime can still be rewarding with the right expectations. If not, I can see this being a quite frustrating watch. And for non-fans, who don't know how the characters should have properly been developed, the experience is still probably worse. I almost want to say a seven is being generous, but at the same time I'm glad a great game like Devil Survivor 2 got an anime adaption. I just really wish it had been a better one.
