Let's get the bad out of the way. The control system is a bit frustrating. It's not something that will prevent you from playing the game, it just takes some adjustment. Your left hand controls the shoot button and movement of Pit while your right makes use of the analog stick to aim and control your point of view. A stand is provided but not necessary. After a half hour of gameplay you should be comfortable, it just takes a little getting you.
The good: fast, fun, & furious. I vaguely remember playing the original Kid Icarus, a side scrolling RPG where you collect hearts, jump on baddies, and shoot arrows. The Nintendo 3DS breathes fresh life into a franchise that many have forgotten about.
Each level is fairly straightforward: 5 minute aerial battle, 5-10 minute ground level (Zelda-esque) hunt for baddies, then a boss. The recipe is simple, but it's fun and I keep wanting to go back for more. You collect new weapons, and can redeem hearts for rewards & the like.
The 3D aspects of this game are flawless, though not entirely necessary if you find that aspect of the device distracting. A beautiful world with a fun story-line. Lots of laughs and hours of fun await.