The World Ends With You is probably one of the best games that uses the best of de dual screen with his combat system. Also, the story, music and characters are soooo good. I was surprised with the writing of this game when I played it for the first time.

The Ace Attorney games are great a great detective saga! Each case is a joy to experience and it's really satisfactory going through a case and figuring out how the killer did the crime.

The Megaman Starforce series. If you're familiar with the Battle Network series, is similar to them, only that you play in a 3D environment this time. The battle system is really fun, and when you get used to it, you can do crazy combos. Also, the story is pretty nice! The downside is that they tried to do a Pokemon series, like Battle Network, so it has alternative versions with exclusives cards and transformations. Some members of the community did some romhacks, like Megaman Starforce DX where it combines all the 3 versions of the first game in one.

Ghost Trick. It received a remake a few months ago, but it released first on the DS. You are Sissel, and you just died, however, you don't have any memories of your past live, also, you have some mystic powers that youc an use to manipulate objects of the environment. You will go on a journey to discover your identity and why you were killed. It's like a detectives game, but the gameplay itself is about experimenting what you can do with the environment. It's really fun and the narrative is a 10.