It's a very fun game with some witty dialog and dynamic game play. I was surprised just how much replay value is there.
The rail shooter part of each level is very intuitive and fun. While it can be a little difficult to find a comfortable way to hold the 3DS with one hand, it didn't seem to bother me too much unless I played for an extended amount of time. When playing on higher difficult levels, this part is quite a challenge.
The ground 3D shooter part of each level is great but the controls suffer here a bit. While this part of each level is somewhat easier, you have a lot more to deal with considering that you can have a range of power ups to use. You only have three power ups visible at a time on the screen and you have to use your stylus to flick through them. This takes your attention away from the action on the top screen which can cause Pit quite a bit of damage if you're in the middle of a fight. Also, it's not always easy to get Pit to turn around 180 degrees without him going a bit out of control.
All in all, though, I've been enjoying this game and have been quite surprised how much replay value there is. Each level has various areas that can only be accessed depending on what level of play you have things set at. There are also some hidden areas to find and secret weapons to locate. The thing thing shines the most about this game, though, is the music. It's some of the best work I've heard in a long time.