Moero Nekketsu Rhythm Damashii: Osu! Tatakae! Ouendan 2: The Longest Title Ever, has 19 full-length licensed Japanese pop and rock songs, up from Ouendan 1's 15. (Interested folks might find a song list here.) Like in the previous Ouendan, the goal is to cheer along with the music by tapping circular marks along with the rhythm. Some basic new features include being able to quickly see your best score and grade on each song directly on the song selection map, saving replays of your performances, being able to quickly skip song intros, and little perks like that. You can even save a recording of a performance and then play against it in a faux-multiplayer mode if you don't have any other friends to play with (they'll be needing their own copies of the game, y'know).
Once again, the story follows the Ouendan we know and love as they help people out of tough situations, but it seems like a rival Ouendan group has moved into town. The stages are divided between them until the final stages. And then something interesting happens... no spoilers here, but here's a hint: Ouendan has to save the world, again! As it's an import game, all of the text is in Japanese, but the language barrier is a huge non-issue. The game is simple enough to understand, and many people consider the all-Japanese interface part of its appeal. It seems like a couple of the story sequences are a bit weirder now, actually... selling shoes to aliens seems like a bit of a stretch.
Ouendan has been one of the best games on the DS since it came out, and Ouendan 2 is a worthy sequel. There aren't any radical changes, just a bigger, nicer version with 19 new songs. Owning at least one of the Ouendan games can't be recommended enough.
Pros:
Lastability: 9.0
Unless you can S-rank everything in a week like some kind of Youtube superstar, you'll be playing this for quite a while.
Final: 9.0
This is a fantastic game, and comes highly recommended for purchase. It's easy to understand, especially for an import, and it's incredibly fun.