Feels like a Saturday morning cartoon, and in a good way.
Every character is surprisingly distinct and memorable, if a bit beyond quirky, which deserves some real appreciation. Even characters I didn't like were entertaining to listen to as I blasted through the various levels. I found the ongoing dialogue during the levels kept things feeling frantic and fun. Like all other reviews, the high-flying shooter sequences were by far the best part of the experience. That said, the ground levels are also good, if a little more taxing on the wrist. What's really missing on the ground levels, in my opinion, is the Z-targeting made famous in the Legend of Zelda series. Without control of your targeting I occasionally ran into issues with enemies getting behind me and having a tough time flicking the screen with the stylus to get a grip on the situation. That's where a lock-on mechanism of some sort would have really helped. In some cases I wish the camera would have paned more automatically, especially when driving the futuristic kart or whatever it was.
Most pleasing is the sheer amount of content. Though I finished the campaign (a surprising number of chapters I might add) there's a lot of weapon-fusing and online battles to play around with. Also, I like the difficulty slider where you can adjust the brutality of the experience. The way this works is you bet in-game currency (i.e., hearts) at a rate that correspondences with the difficulty you select. Harder difficulty levels have larger rewards but failure comes at a price (you lose the hearts you bet). It's a nice concept and allows you to tailor the experience to your play (well, I would say tolerance...) level.
There have been a lot of complaints from other reviews about hand-cramps. It is an issue due in large part because you are trying to control so many aspects of the game simultaneously. For example, in the high-flying shooting levels you not only have to use the stylus to aim, the trigger to shoot, but also the circle pad to move Pit onscreen to dodge. It's similar on the ground. That's basically trying to do three things at once which I found to be a little disorienting at first, though you do get used to it. Unfortunately, even after you get used to the controls it physically can drain your wrist. What I found is I can play about one level at a time (about 10-15 minutes). While I tried the included stand and it seemed to work well it seems impractical to carry that around for a handheld so I honestly never used it after I first tried the game.
Most reviews seem to hover around an 8-8.5. I'm giving it a 9.0 because, while it certainly has a few issues, I feel the long-term impact of the game will really be strong. The additional pilot-cartoons put on Nintendo Video should, if it hasn't already, lead to a real Saturday morning cartoon. I wouldn't watch it (I'm too old for that sort of thing...), but I think younger folks would love it. The fact that the director indicated no sequel for awhile is good too, because the game is jam-packed with enough content to last until the next handheld generation. That's one thing I like about Nintendo, they usually limit their biggest franchises to one game per system. In my opinion, the quality is much higher because of it.
If you own a 3DS, this game should be in your collection. Shoot me a PM with an FC so we can play online!